there is no recent increase in vacancy rates
You're looking at the wrong stats. When people are forced to spend more on necessities, they don't cut necessities. They can't. They're necessities.
They cut luxuries.
One such relevant stat, would be piracy spiking. Not to mention the spike in homelessness if we are talking about the US.
You yourself point out that housing is not keeping up with need. Things can absolutely be getting worse (and they are), while at the same time not showing up in vacancy rates. The well-off can be moving into new homes faster than the poor are moving back in with parents. Or going homeless.
Another stat is the average age at which people buy their first home increasing.
Another is the ratio of renters increasing in relation to owners.
investment companies are seeing that housing is shooting up in value already, due to low rates of building, hence making it a more attractive investment relative to other things. So they buy them up and charge high rents - but at the same time all the individual owners of rental property also see that they can charge high rents, and do so. All we've done is swapped who is screwing renters, not by how much.
This is a distinction without a difference. You're saying the chicken came first, while I'm trying to explain chickens come from eggs, and the entire relationship between the two.
Increased consolidation increases the co-ordination of price hiking, hence increasing "how much" screwing is going on. But that doesn't mean a tiny bit of screwing can't get it started.
I'm saying it has gotten so bad because the problem feeds itself. By allowing more investment, the screwing gets harder.
All we've done is swapped who is screwing renters, not by how much.
This is a truly insane take. You're saying if all rented properties were owned by single landlords who owned no other properties, rents today would still be just as high?