Most of california's illegals, the state with the most, came between 1991 and 2008. Though as the sanctuary state many came since.
In that time period the average home went from 80k-200k to almost 1 million last year, especially in the western half of the state.
It is the sanctuary state, and also the one that brings in the most chinese and indian legal immigrants for tech companies, doctors, engineers, coders, etc.
Most new private homes bought in recent years are bought by indians and chinese. They often then move in thier entire extended families, which are not doctors and engineers.
Also many companies often backed by chinese investors buy up a lot of the supply to rent them.
Then all the people making under 100k a year must live multiple adults to a home to pay the bills.
Apartments are like 2-3k a month, first and lasts months rent plus security deposit, meaning you better start with about 10k in your pocket to get an apartment and pay the bills and have enough for other basic necessities your first month. This is most coastal counties where the economy is.
The illegal immigrant families do the best on the low end of the economy in the sanctuary state, not having to pay income taxes, able to get drivers licenses and live like normal citizens and since income is off the books qualify for free medical, and food stamps for children even if they really earn twice what allows someone to qualify. All thier children also get free college, no need to save for that.
You can make 50k landscaping, claim to make under 20k and also owe no taxes without fear of arrest as an illegal while legaly driving your pickup around on a ca drivers license.
Actual citizens have it harder.
The invaders conquered the state then rewrote it to benefit invaders over citizens.
The insane housing costs are directly related to foriegn invasion and the resulting supply and demand issues.