So, well, indeed, a good plumber should not see extremely lean years.
(Anecdotally, my son works as a building systems maintenance engineer, without a college diploma. Of course the market for such jobs ebbs and flows, but seems to never dry up: city buildings still need their elevators, HVAC, fire alarm, access control, etc systems working, no matter what.)
Building more housing should lower the effective price of it, and allow many new home buyers or renters to enter the market.
[1]: https://www.pewresearch.org/fact-tank/2020/09/04/a-majority-...
It'll be interesting to see how things play out. I think the shift of older millennials out of cities combined with the relatively smaller generation replacing them will likely cause a reversal of a lot of the urban price growth in the past decade in places like New York. Rents are already reflecting that, but sales prices have more hysteresis.
source: 15 year professional Urban Planner in California