Spring Break is fairly new to the area. Prior to that the college students would hit Daytona, Panama City, or Key West. And long before that Fort Lauderdale was the Spring Break destination (showing my age).
The traditional family-owned restaurants started being driven out in 2014, to be replaced by new investor backed concepts because the rent was too high. Joe's Stone Crabs owns it spot and isn't going anywhere, I can't say the same for the restaurants around it. AirBnB didn't cause restaurants to close, speculators did.
Finally, it is the season of the snowbird. Every beach is packed with foreign tourists staying in their vacation homes on 6 month visas. When June arrives they'll leave, they always do.
Also, prior to this spring break there was only a few reasons to go to Ocean, Spring Break, Memorial Day, and Fourth of July. Now, city council and local organizations have planned street festivals basically every weekend between here and eternity.
All to say that very little of what's going on on Ocean Dr has anything to do with AirBnB.