When judging from lower-speed services and mobile access, there is ample competition. But Mr. Wheeler’s analysis leans on the definition of high-speed service at download speeds of 25 megabits per second or higher. He terms the 25-megabit threshold “ ‘table stakes’ in 21st-century communications,” when households are increasingly using online connections to download movies and music. At that level, 55 percent of consumers have only one choice of provider, according to the F.C.C.

Last month, the commission redefined basic broadband service, adopting the 25-megabit standard, up from four megabits. The move was opposed by the two Republican commissioners, including Ajit Pai, who says there is a “very competitive marketplace.”

With or without the new net neutrality rules, cable broadband faces numerous competitors. They include upgraded versions of the DSL, or digital subscriber line, technology offered by most telephone companies; next-generation wireless service; Internet access from low-orbit satellites; and very-high-speed fiber optic connections to homes.

Each has promise, analysts say, but also limitations. The telecommunications companies have employed a variety of techniques to increase the performance of DSL and have made progress. But cable remains a more capable technology, and keeps advancing.

“The gap between cable and DSL is getting larger,” said Craig Moffett, a senior analyst at MoffettNathanson Research.

Mobile wireless services are improving rapidly. But even if high speeds and steady transmission could be achieved, analysts say, the cost to consumers on metered data plans would make them inordinately expensive for households streaming movies on Netflix, for example. Mobile wireless is for data sipping, not gulping.