There have always been parks which cater to long term residents, and parks which focus on transients.
I can see where a core of long term residents is vital to survival of a park, especially in popular winter destinations. Those parks would not be there for snowbirds without people living there full-time in the summer.
We see a lot of long term folks in DP Class A and very high end 5ers across Texas now. They are folks with families, young kids often school age, following oil industry work. They make very good money, but don't want to live in cheap apartments, and prefer to stay several months so the kids have some type of consistency in school.
I've seen a higher percentage of American Coach, Newmar, DRV Suites, Redwood rigs among that group than anywhere else.
Otherwise, it would be mom and the kids living somewhere several states away, and dad only coming home for the holidays.
I don't particularly like parks with a lot of long term residents - but that's my personal choice. I've stayed a night or two in some.
I've also driven out of some rather than stay.
But I've driven out of some parks with all short-term rigs also.
Live and let live.
If our health gets to where we can't travel - I'll be buying a park model. We all get old eventually.