The unrealized part is the gain in property value, and your equity in it by paying down the mortgage.
But if you consider never selling the house, paying $2k/mo in rent vs $2k/mo in (mortgage + insurance + property tax) is going to start out break-even, improve as the rent climbs to $3k for the equivalent place to live, and then be a larger benefit after 30 years when that housing payment drops to just tax and insurance.
My property tax is considered “extremely high” at $4500 a year.
Rent for $4500 a year is like a closet, even in a cheap place.
Property taxes aren’t a flat rate.
Property taxes county + city are about $4300 per year. They have increased recently, and so has the rent.
If they owner put down a 10% down payment, I estimate their total monthly payment for mortgage + taxes + insurance is about $2000, and will likely remain in that ballpark.
That means rent is currently paying the entire mortage/tax/ins plus $6k per year. At the end of their mortgage that monthly cost drops to about $700, and they will own an asset likely worth $500k+.
I'm from the Netherlands, where property tax is based on the municipality. A 400K home where I live amounts to 423€ in yearly property tax. Rate increases over time are capped. And there's many ways to protest against the market value the taxation is based on.
I suppose the basis for this relatively low taxation is that a huge amount of home owners here have a relatively valuable home (even the simplest of homes is expensive) whilst having a fairly moderate to low income.
If property tax would be 10x as your example suggests, I'd suspect 75% would go bankrupt.
Making a monthly profit and ending up with a paid off, appreciated house at the end is profiting doubly.