The Federal Communications Commission (FCC) announced today a plan to bring affordable high-speed Internet access to all Americans, CNNMoney.com reported.

In addition to a more than $15 billion government investment in infrastructure to bring 100 megabit-per-second speeds to 100 million Americans by the end of the decade, the FCC is calling for a shift in funding to broadband infrastructure from telephone infrastructure to help the country achieve the agency’s goal of 90 percent adoption of high-speed Internet by 2020.

According to the latest study from the Information Technology Industry Council, high costs or a lack of interest stop 35 percent of Americans from subscribing to a broadband provider, though only 5 percent don’t have access to high-speed Internet.

America’s average download speeds of 4 megabits per second rank 15th in the world.

But some say ultra-high speeds of 50 megabits per second or more, which are already being offered by many broadband providers, are expensive and used as more of marketing tool.

“Ultra-high-speed offerings are a marketing game for operators, helping them say they offer the fastest service,” said Doug Williams, broadband analyst at Forrester Research. “The price tag for those services is not conducive to the average consumer, since they don’t see the value in paying that much more for that kind of speed.”

In anticipation of the FCC’s announcement, Google Inc. announced earlier this month that it would test in a U.S. city a 1 gigabit broadband network. And Cisco Systems Inc. recently unveiled a new router that will have the ability to download the entire printed collection of the Library of Congress in one second.

Given that a large chunk of broadband spectrum for mobile broadband carriers is currently unused, following TV broadcasters’ switch to digital transmission, the FCC plans to ask broadcasters to voluntarily auction it off. That would free up 500 megahertz of broadband spectrum during the next 10 years.

But broadband experts remain skeptical.

“The breakthrough in the plan is that it’s an admission that the United States has fallen behind, and that we lack a unified plan to address it,” said Dan Hays, partner at tech research firm PRTM. “But the FCC plan lacks the teeth to effectively implement the full range of recommendations they put forward.”

He said freeing up 500 megahertz of spectrum nationwide is “completely unrealistic,” noting that it is unclear how the FCC plans to pay for the initiatives.