DirecTV, the largest satellite-TV provider in the U.S., plans to launch on-demand movie and TV services this year, according to a report Thursday in The Wall Street Journal.

The move comes on the heels of Dish Network, DirecTV’s major rival, launching a similar offering last year.

This plunge by satellite-TV should serve as a warning to all those who think Internet wonders like Netflix, CinemaNow, or even—take a deep breath—Apple’s sacred iTunes will eventually rule the on-demand movie and TV industry.

Here’s why: Cable and satellite operators are entrenched in over 80 percent of all U.S. TV households. That’s according to research firm In-Stat. Comcast, the biggest U.S. cable operator, already offers more than 10,000 programs on demand, and its cable competitors either already provide it or plan to.

Expect cable and satellite companies to balloon these on-demand services like a party clown on speed.

Once that happens, why bother to pay for a show online from iTunes or Netflix—that then needs to be shuttled to your living-room TV (not so easy for those who are tech challenged)—if you live in one of the 80 percent of homes that have cable or satellite.

Also, the Pew Internet and American Life Project estimates that about half of all adult Americans now have high-speed Internet at home. That means less than 50 percent of homes have broadband—presumably, most homes have more than one adult.

You need a high-speed connection if you want to download a movie in less than a day. So not only do iTunes et al have the 80-percent hurdle to overcome, they’ll also need a lot more broadband penetration before any claims king.