Florida had derelict boats that were abandoned and while existing legislation may have prohibited these boats from anchoring it was sketchy at best. Most municipalities were reluctant to act. St Augustine for example had a real mess for years but now was able to clean up it's waterfront by making it a mooring field. Yes the communities are making money from these mooring fields but I don't think that was the only reason.
.While Aythya Crew may not have ever been "harrassed" by the authorities or home owners, Miami Beach police used to (I don't know if this is still the case) only allow anchoring within their boundries for 5 days per month. In Sunset Lake, again in Miami Beach, two home owners regularily harrassed boats at anchor
.It happened to me. The last time I anchored in Miami Beach there were only a handful of boats and none around Monument Island when a few years before there were hundreds. Marco Island was infamous for harrassing cruisers and in Lake Sylvia in Fort Lauderdale similiar behaviour was exhibited by the authorities. This was done because of pressure by the landowners around the waterways.
The Marco Island tactics resulted in one cruiser whom they harrassed taking them to court and winning. Municipalities panicked fearing a huge influx of undesirables, like me, anchoring in their backyards and so they got the state to introduce the mooring field law.
There are still lots of free anchorages in Florida but the number within municipal limits are quickly disappearing. As long as Florida municipalities make money and get rid of derelicts, free anchorages in Florida will be a thing of the past.