New competition and new technology are conspiring to snatch viewers and advertisers from the region's big terrestrial TV operators.
But the industry stalwarts are, for the moment at least, staying on top by doing pretty much what they've always done - and teaching the newcomers a thing or two along the way.
While it is generally accepted that the quality of programming available on free-to-air television has improved as new terrestrial broadcasters enter the market and as cable and satellite penetration rises, observers say there's more to the terrestrials' success to date than the fact that, often in the past, there's simply been nothing else on.
In Hong Kong, for instance, TVB takes 80 per cent of advertising dollars going into terrestrial TV, and two-thirds of all people watching any television at all. ATV attracts just 22 per cent and two per cent on its Chinese and English channels respectively, according to Nielsen Media Research figures for the first three months of this year.
The launch last year of PCCW Now Broadband TV and more recently of Galaxy has not yet shaken TVB's position - it has put up ad rates by more than 10 per cent in some cases so far this year.
Ronald Jones, TVB's senior manager for business development and investor relations officer, says he's not worried. This is despite Nielsen figures that show ad revenue for cable TV rising 166 per cent in the first quarter of this year compared to the same period last year, albeit from a very small base and with viewership still a fraction of that for the terrestrials.
"The television environment in Hong Kong is clearly changing and becoming more complicated ... but the problems we face in our free-to-air business in Hong Kong have long been more related to the ups and downs of macro-economics than to competition," Jones says.
"We don't feel that pay-TV has punched any significant hole in our free-to-air ad revenues thus far. These players reach different, much smaller-scale markets, and, as likely as not, are expanding the overall TV advertising pie rather than taking business away from existing players."
Rates have also been rising at Thailand's most popular free-to-air channels.
The country's recent return to prosperity is fuelling a consumer boom that in turn has triggered a lift in adspend. This has all been to the benefit of Channel 3 and Channel 7, which between them command about 75 per cent of the prime-time audience, MindShare data shows.
Newcomer Channel 9 is, however, attracting families, iTV is appealing to urban, middle to upper-income young adults and families, and Channel 5 is having some success with a more conservative, middle to low-income viewership.
And, as Publicis Media Groupe regional director of consumer insights Craig Harvey points out, cable and satellite operator UBC is not allowed to compete for advertising, or not yet, at least.
"In recent years though the Government has allowed UBC to carry public service announcements, seen by many as a first step towards allowing them to sell their own advertising space," Harvey says.
Ad revenues at channels 3 and 7 are still rising, for the moment. While revenue at iTV rose 39 per cent in the first quarter compared with the same time last year, that at Channel 7 was also up, by 22 per cent, Nielsen figures show.
Phil Rich, Nielsen Media Research's Southeast Asia executive director, says the appeal of British and American-style game shows and "real life" contests in Asia is clear, but that the well-established terrestrial channels have proved they know what their viewers want, no matter if the rest of the world sneers at it.
"The underlying story is still that locally produced dramas of various sorts have been really the strong audience deliverers over the last five years or more," he says.
The networks are also, increasingly, buying in each-other's locally made content - witness TVB's success selling its programmes, for instance, and the fact that in Indonesia last year, the most popular show on the small screen was an Indian movie.
Cable and satellite channels are investing huge sums to producing Asian-made, local-language content and special feeds dedicated to viewers in individual Asian markets - in essence, what the terrestrials have been doing on a much smaller and more modest scale for years.
Rich observes: "Star's strongest markets are the markets where they're behaving like a local broadcaster - India and China."
In Thailand, meanwhile, MindShare general manager Kevin Clarke says it is the older terrestrials' own success - and not competition - that could ironically be their downfall.
"With demand strongly outstripping supply, channels 3 and 7 are under little pressure to negotiate discounts," he says. "And as long as economic conditions remain positive this situation will get worse.
"Television price inflation is probably the largest threat within the media environment over the next five years."
In Singapore, new terrestrial competition is benefiting viewers as long-established MediaCorp and relative newcomer SPH MediaWorks battle for public attention with new programmes - often local versions of international so-called reality shows.
Nielsen data shows that in evening prime-time, MediaWorks' Channel U has just overtaken Channel 8 in terms of share of viewers. Advertisers are making the most of the competitive environment, but neither of the media companies can really be enjoying the competition, given the limited size of the market, and talks of a merger between the rivals persist.
In China, mergers have been taking place not only between terrestrial broadcasters but between terrestrials and cable stations. Rather than competing against each other, these new bed pals co-operate by ensuring they don't schedule highly popular programmes at the same time as each other, for instance, and try to take share from the national and provincial channels, which, Harvey says are in turn revamping their programming.
Recent restrictions on the amount of advertising time allowed has not yet led to dramatic changes in rate cards, although many advertisers are paying more than they were a year ago because the discounts that existed before are being trimmed or scrapped altogether.
In India, meanwhile, the long-dominant state-owned terrestrial broadcaster Doordarshan remains at the top of the TV tree, although it generates less advertising revenue than Star, which has the second-highest reach figures.
This market perhaps more than any other in the region illustrates the success - both in ratings and revenue terms - of providing locally made content that suits local tastes. Apart from Doordarshan and Doordarshan News, which is also hugely popular, all other channels in the top five for weekly reach are general entertainment channels broadcast in Hindi.
This simple truth is the reason Nielsen's Rich says the terrestrial channels' huge appeal to viewers and advertisers will remain, at least in the short term, even as more Asian householders are subscribing to cable and satellite or watching broadband TV on their computers. Says Rich: "If you ask 'will channels like Channel 7 and 3 in Thailand and TVB in Hong Kong still be the dominant media force in their market in five years time?', you'd have to say the answer is yes."