The problem is the gobbling up of most stations by Cumulus Media and iHeartMedia.
Not even close. Cumulus owns 447 stations, iHeart owns 850.
As of June 30, 2017, there are 15,512 radio stations (4646 AM's, 6755 commercial FM's, 4111 non-commercial FM's).
That may be true if we’re looking strictly at the number of licensed stations and treating each one as an equal citizen of the broadcast media landscape.
But if we weighted the relative “value” of those stations based on the number of listeners or the radiated power of their transmitters, I think we’d get a figure that shows a much tighter grip on the airwaves by a relative few owners (iHeart, Cumulus, etc.).
For example, here are the top 10 FM stations for New York (based on the most current list I could find quickly):
1. WLTW-FM — 5,013,600 - iHeart
2. WHTZ-FM — 4,388,300 - iHeart
3. WKTU-FM — 4,136,500 - iHeart
4. WCBS-FM — 3,591,800 - CBS, being sold to Entercom
5. WBMP-FM — 3,000,500 - CBS, being sold to Entercom
6. WNEW-FM — 2,838,700 - CBS, being sold to Entercom
7. WAXQ-FM — 2,761,900 - iHeart
8. WQHT-FM — 2,666,100 - Emmis
9. WWPR-FM — 2,577,600 - iHeart
10. WPLJ-FM — 2,299,900 - Cumulus
iHeart (the #1 owner of radio stations in the country) alone owns half of the top 10 FMs in a single market–and Cumulus and Entercom own the #2 and #4 largest U.S. radio station portfolios, respectively.