Well, no, the sky is not falling.

Some people need a world in which they have exactly one employer, as well as a fixed bi-weekly salary, dropped into their bank account, because that is how they want to live. Good for them!

I like to scavenge my surroundings for opportunities, and make money from stuff that occasionally happens to drop from a tree. Once in a while, I meet people who like to do a deal with me. I sell. I buy. I trade. I just love it. I am simply NOT interested in a boring world of bi-weekly wages paid into a bank account.

I do not consider tycoons to be a threat. It is the little, petty SJW bureaucrats that take too much of an interest in other people's business who are the problem.

>The people renting from him may never buy a house, given that building new ones here is becoming hardly possible due to zoning

You nailed the problem, actually. Stop giving authoritarians too much power to tell us what economic activity we can do. Stop the endless mess of subsidies which make honest business unprofitavle. Your argument supports the person you disagreed with.

Well it must be represented by one simple thing: rental yields. What is the rental yield for a typical property in your place? If it's going way up, you can easily afford buying instead of renting so you don't have that problem (at a rental yield of about 6% or so, a mortgage becomes smaller than the rent). If it's going way low, it's a stupid idea to buy and owning will probably never pay for itself and lose money long term. I know a lot of places where rental yield is under 2%. Why would anyone buy there? (explanation is usually: to park dirty money).

And it's not due to zoning. Zoning exists so that load of excess people does not make a neighborhood unlivable, or there will be too much traffic and getting to and from job becomes impossible.

Wanna fight it? Push employers to let people work remotely. It's not possible for low paying jobs e.g. waiters, but these don't buy or rent anything anyway, for most professions where people have a shot of getting into a real estate market, there is such option. Let people work remotely and suddenly you'll realize there is a shitload of almost free real estate around.

Well, that assumes someone wants to sell a house, or that you're allowed to build a new one. Neither of those may be the case.

Or that you can afford to save for a down payment on top of current rent and other living expenses.

Well there's always someone wanting. There is always a real estate market, always. In absolutely all places you can buy or rent. If people find ways to make living in a particular place less important (say by enabling remote work), things will become easier.

Also well, the very small fraction of homeowners who have a privilege of owning these places have effectively won a lottery. They naturally have to protect their winnings. Basically for every one of them there is a 1000 or more of people who own place out of a highly sought-after area like the Valley where his real estate does not appreciate and brings no rent. If you take the averages, all-accounted yields from real estate are laughable and way under the yields from a stock market.

Can we say that someone who bought stock that skyrocketed 1000x, 20 years ago, has to be penalized for it, or be forced to sell? It is either a very smart insight (or inside, but in case of stock it's way way way more probable than in case of real estate), or just blind luck. It doesn't mean same trick is reproducible at any given moment if you have money to buy, the mathematical expectation of profit you will make buying anywhere you could pick at all, is quite low and you better go to a stock market.