Do you expect an upsurge in retirement? Otherwise it should be a pretty steady rate, year-to-year, no, unless major companies with major layoffs favoring seniors happened in those regions this year...
Yes, the population is aging and retirees are a rapidly-growing segment.
The boomer generation is retiring now, no?
Yes, but they all didn't grow up in three main regions, nor during a narrow time window. In other words, if this were solely due to retirement, I'd expect to see a more gradual increase and in more places.
Considering that NYC, Chicago, and LA are the three biggest cities in the country, I would say, yes, quite a few of them grew up in these regions. If anything, boomers would be the only generation that could afford living comfortably in said regions.
Yeah but parent said "now", and I would not expect a big jump. You may be including retiring "now" + already retired [who no longer want to or can afford those places and also are moving].
Yeah, to be clear, I don't think this is the only contributor - I'd imagine taxes and cost of living definitely have an impact, among others. I do think some of these factors might work in concert too though - it's not difficult to envision people entering retirement, who own their abode in gentrifying areas and have seen property values (and taxes) go up, deciding to sell and see that money go further in a lower-cost-of-living area.