According to a report released by the U.S. Commerce Department's Economics and Statistics Administration, far more competition in Internet services exists at slower speeds than at higher speeds.
Specifically, at download speeds of 3 Mbps, 98% of the U.S. population had a choice of at least two mobile ISPs, and 88% had two or more fixed ISPs available to them. At 10 Mbps, the typical person is able to choose among two fixed ISPs. They also have the option of subscribing to any of three mobile ISPs at 10 Mbps. (The report analyzes fixed and mobile service separately.)
At speeds greater than 10 Mbps, 37% of the population had a choice of two or more fixed-service providers at speeds of 25 Mbps or greater; 9% had three or more choices.
The report also indicates that broadband service of 100 Mbps or greater is not available to 40% of Americans. Of those with access to fixed broadband service at this speed, 8% of the population had access to two or more providers, and 1% had access to three or more. Only 3% of the population had 1 Gbps or greater available, and none had two or more ISPs at that speed. Mobile service is virtually non-existent at download speeds of 25 Mbps or greater.
The full report is available at http://www.esa.doc.gov/Reports/competition-among-us-broadband-service-providers.