Perhaps the OP could even reframe the question, “Why are so many people homeless now, compared to many decades ago?” (Forgive me, I’d obviously like to reframe it that way.)
It’s because a few decades ago, the cost of housing became artificially inflated due to a combination of speculative buying and irrational market forces. While undoubtedly housing has usually been, in the U.S., the single highest cost per month for any individual, it had not, until then, been so disproportionately expensive, relative to every other indispensable need. While the market has somewhat “corrected” for less demand and more supply, and less artificial (over)valuation, there is still a base value, especially in the locales perceived to be most “valuable” in which to live (regadless of how concretely “valuable” a particular abode is or is not, as an abode). So if a person has the bad luck to live in such a high-“value” location, and to be simultaneously out of work, the risk for homelessness is extremely high, especially in areas without also a lot of shared, safe housing options. (Rooms in houses, or rooming houses themselves.)
#2 is Employer Attitude, which means zero loyalty, zero notice for being laid off, and “at-will” employment. It’s brutal and inhumane, i.m.o. and in need of corrective regulation. It flies in the face of Catholic social justice.
#3 Extremely competitive job markets: Thiscan come into play in a Perfect Storm with #1 and #2 if you have the bad luck to be in a job market location which is saturated with overqualified people doing precisely (or nearly) your job. There are 2 or 3 such locations in the country: Washington D.C., the SF Bay Area, and I believe Seattle is third, but someone can correct me on that. It is not NY, by the way.
#4 Employer outsourcing
#5 Employer guerilla tactics, which means under-employment, often (no benefits), falsifying job interviews with promises of bonuses, benefits, raises, permanent status, etc. and then not following through when your cherised Bottom Line is not met.
#7 Under-regulation of Employment, and zero social aid for those who cannot afford a lawyer but have been wronged by broken promises, lack of supervisory oversight, etc.
The above help to account for a burgeoning homeless population since around 1985, changing the “face” of homelessness to include all kinds of non-mentally-ill and very skilled people. I personally have met plenty of these.
Got to run, but that’s it for starters.