Yes, it's entirely possible for multiple sports stations to survive, and thrive. Sports is a huge business. Look at all the sports bars, all the local teams (3 pro, 3 minor league baseball, 1 minor league hockey, countless colleges, and the huge OSU fan base in NEO), that literally make millions on sports fan revenues. And, there must be about a dozen sports cable networks. Yes, the sports pie is big enough for multiple stations to chase the market.
WTAM is still first and foremost a news/talk station that carries sports, and ranks near the top of the market. WKNR (when Arbitron still posted their numbers), beat WKRK by a significant amount in the 6+ numbers. The stations with the challenges? WMMS (probably ranks very well in it's target 18-34 male demos, but not a top 10 market station overall), and WKRK (limited signal and promotion). Sure, they're FM, but both 850 and 1100 have done well in keeping target male demos tuned into the AM band.
As always, it's the personalities and hosts that draw you in, and so long as the station is listenable when you want to hear it, doesn't matter if it's AM or FM. And, if you have a host with a significant following, people will keep listening to you.