The point of GP is that the number of illegal immigrants has in fact dramatically increased over that decades-long period, and the people continuing to claim 11 million are at best grossly uninformed.
> If I hadn't been hearing that the illegal immigrant population has remained unchanged at approximately 11 million for decades
The entire point is that OP is complaining about repeatedly hearing a falsehood. Hence:
> I think a lot of people are truly in denial about just how many illegal immigrants are in the country, and they all need housing.
There are far more than 11 million illegal immigrants in the US. When you take into account that as an objective matter of fact we are talking about far more than 3% of the population, your argument "no way 3% of the people are causing 30% of the price rise" becomes moot.