Money is a token that is related to assets. Money without physical assets is akin to me having a bundle of monopoly cash in my pocket. Its the relationship that the token has to the assets that gives it worth.
So, forget about the very mobile token, and tax the asset that it relates to, as they are, generally, considerably less mobile.
My car example was maybe confusing, as cars seem somewhat mobile. Here in the uk, a significant part of our countries "wealth" is in real estate. The clue for that is, quite literally, in the name - REAL ESTATE, not intangible assets.
That's not going anywhere at all.
The bottom line is that, sure, you get things like facebook or whatever that seem like they are ethereal but the money always ends up, somewhere along the line, being tied to actual "stuff", rather than just being a number on a computer monitor. The actual stuff isn't as easy to move to tax havens as the numbers on the screen.
This thread was about mortgages -
A couple of generations ago, people owned their own homes, with one person working and one person normally staying at home. Working fairly standard jobs.
Then it was two people working fairly standard jobs.
Now we have seen massive price inflation in the property market, such that most people working "standard" jobs, without some cash hand-out from their parents, are excluded from home ownership.
Again, the uk, even more so than other countries, holds its "wealth" in real estate. With spiralling wealth inequality, an increasing amount of the bricks and mortar is being held by a smaller and smaller number of people.
It's not easy to move it to Portugal.
As a closing point, if you have doubts about wealth being held in real-estate, id remind you of the 2008 issue, and what caused that. Real estate is not just a little bit of nothing. Its significant. And not very mobile.
The error here is blaming corporations for the increase in residential housing. It is an increase related to the individual. You (not you specifically, but the average citizen) don't live frugally like a one income household a couple of generations ago nor do you live like one a generation ago with two incomes, and the housing quality structurally may have been fine, but it would've been smaller and with much less comfort let alone decoration inside.
Borrowing on top of that and decreasing the housing supply and making it harder to build doesn't help, either.
When individuals stop caring about whether or not they ever own their house, the price will go up - due to the individuals, not someone victimizing them. Once you decide that paying the interest on a loan is just as good as paying off the loan, then the price of the item being bought without unlimited supply will tend toward being set where the price of paying the interest is.
It's no difference here vs. there.
60 years ago, the average house was 2x income. It's not that the houses were so much more affordable, it's that they had almost nothing in them and were smaller. at one point before 2008, that had risen to 11. Houses were probably twice as big on average by then and everyone thinks they need to be a lot nicer with more amenities, and the idea that it's no longer sensical to pay off a loan just drives up the price further because the bogey is being able to make a payment, not to pay with the goal of not making a payment.