Google, which acquired online video-sharing company YouTube last year, said the Internet is not designed for television.
It even issued a warning to companies that think they can start distributing mainstream TV shows and movies on a global scale at broadcast quality over the public Internet.
Google instead offered to work with cable operators to combine the cable networks' high-quality delivery of shows with its own technology for tailored advertising and video searching.
One cable chief executive, Duco Sickinghe of Belgian operator Telenet, said it was "the best news of the day" to hear that Google could not scale for video.
Google was welcomed with a mix of fear and awe by the cable TV companies, which are concerned that Web companies will try to steal their lucrative TV business. The Internet on the whole is a mixed blessing, cable carriers said.
Broadband Internet delivery to homes and small businesses is one of the most lucrative segments of the cable TV industry, but heavy investments in infrastructure are needed to meet the rapid rise of Internet file swapping and video downloads.
The data involved in an hour of video can equal the total of one year's worth of e-mail.
"Most of the IP (Internet Protocol) traffic is peer-to-peer (file swapping), and most of that is video. Every year, we have to invest substantially just to maintain the user experience. In fact, it has actually decreased," said Richard Alden, CEO of Spanish cable operator Ono.
"(Internet service providers) don't like to talk about (the fact) that just to stand still, they have to invest," Alden added. "But you cannot keep investing at the same clip."
Research group Gartner estimates that 60 percent of the Internet traffic that is uploaded from computers is peer-to-peer traffic, mostly from consumers swapping films and TV shows through select user groups and BitTorrent.
Financial advisers praised the cable TV industry because, unlike the large telecommunications operators, it has been expanding and has been more efficient with capital and more profitable.
Shares of cable operators trade at about nine times forecast 2007 earnings before interest, tax amortization and depreciation, while telecommunications operators trade at about six times, said Charles Manby, Goldman Sachs' global co-head for the telecommunications, media and technology industries.
Cable operators are set to return to capital investments of a modest 10 percent to 12 percent of revenues, but they can be forced to spend much more due to outside pressures from increased Internet consumption and from rival telecommunications operators that upgrade their broadband Internet packages to fiber-optic superspeeds.