What would make you think the landlord's interest rates would go up? Its unlikely that any mortgage they have will have a floating interest rate. Borrowing more money will likely be at a higher interest rate, but deals that are closed aren't going to change.

I assume you're used to fixed rate mortgages. A whole bunch of countries don't have those. Actually I only know about the US having real fixed rate mortgages. Other places either have mostly variable rates or some sort of fixed period and a mechanism to bring up the rate in some conditions.

That sucks for folks then. I'd definitely push for that to change. In the US you may not always get the best interest rate but it'll usually be the same for the entire length of the loan.

My own payment going way up. There are no full-term fixed rate mortgages where I live - I can get it fixed for 3-7 years (and 7 gets me much worse interest rate).

That sucks. In the US we typically get fixed rate loans for the length of the loan which could be as long as 30 years.

What about variable rate mortgages?

Before the 1980s it was considered unreasonable risk to rent out a property that was not owned in the clear. Maybe this means we might want to being considering living by some of the older rules, Glass-Steagall being another prominent example among many others.

No, the mortgage rates are fixed for 30 years. So any LL that bought when rates were 3% continues to pay that for 30 years even if rates rise to 7%. That's why being a landlord works out much better than a renter.

And if you do buy when rates are high you can also refi when rates fall.

(Edit: This is in the US; adjustable mortgage rates are more common in other countries)

Why would their rates go up? They should have a fixed mortgage rate. My mortgage rate didn't hasn't gone up at all.

If it's a new purchase, sure.

There are other options, like moving in with parents, group housing, van life, or even going homeless. So long as people can afford it they’ll usually avoid those options but once they’re tapped out they are no longer able to. There is a limit for how much rent can be raised even if buying becomes more difficult to finance. I don’t think we’ve ever hit that limit in the US in recent history. Landlords not being able to raise rent to cover mortgage payments would be a new thing they probably haven’t planned on.

Do you rent? If yes, how much does rent have to increase before you decide, "Ah yes, I would much rather be homeless, but at least I am voting with my wallet, that will show the greedy landlords not to raise rents!"

I personally cannot think of a limit at which I would decide to be homeless. I would much rather have a home to live in than buy any food beyond what sustains me, or get new clothes, or go out for any entertainment reasons. I believe I am not the only one in this. Thus, from a purely economic perspective, the landlord in these cases are "leaving money on the table", i.e. they could capture more of my surplus income if rents happened to increase in a coordinated fashion. Unfortunately, there is nothing in Econ 101 which tells you why that would be bad or unsustainable (social unrest etc.) and thus these concepts will be hard to grasp for people who do not have to live this life.

I’m not the marginal renter, and from the sounds of it neither are you, it’s the person who can barely afford rent and doesn’t have good options to chose from. The person deciding between fuel, food, medicine, or rent. The person rationing their insulin. How do you think many homeless people became homeless to begin with. They didn’t all start out as drug addicts.

And as mentioned homelessness isn’t the only option, I know plenty of people who have moved back in with family or still have room mates into their 30s and 40s.

I think I agree with you, and so I will not risk talking past each other.

Let me just take this spot to point out that from a landlord's perspective renting out two units at 100% is economically equivalent to renting out one unit at 200% while letting the other unit sits empty. However, it is strictly worse for society at large because of the artificial scarcity of a basic right.

You had me until this "artificial scarcity of a basic right."

Housing is not a natural right. Rights don't have limits (until they harm someone else), so something like speech can't be artificially scarce.

That is a matter of ideology. The natural rights doctrine you're using to claim rights cannot have limits up to the right of someone else is mostly an artifact of Abrahamic religions and is not founded by much in the way of logic.

There is no hard reason why socially adequate housing cannot be considered a right.

That's not a hard argument, it's a soft argument. But generally these rights are backed by a responsibility to society in general as a collective.

I'm not part of your collective nor social contract. I do pay use taxes and fees for public goods such as roads.

When did society get the responsibility to bail out the high-paid bankers who failed in 2008/9? Occupy wall street didn't think we should bail them out.

Soft vs hard means what? More like a slippery slope until too big to fail bankers are rescued by the working class collective.

Rights are endowed by our creator (higher power or whatever your words may be). Rights are not backed by a responsibility.

I support charities for these activities, not compulsory taxation by government.

(And I wish people would comment rather than just downvote, as a discussion requires comments.)