I know everyone on MMM is all about keeping mortgages and investing the difference,
No, not everyone feels this way. Buying a modest house and paying it off quickly was one of the best choices I've made. I don't care if the investment math says I could've made more long-term -- that's hypothetical math, based upon (reasonable) assumptions, and assumptions don't always come true. I love knowing that every brick is mine, mine, mine. A part of this is based upon the fact that i was a poor kid and was worried more than once about "making rent"; nothing is as good as knowing that my home is mine, mine, mine.
so are you using that same "hypothetical" math to retire on ...
and the govt can take your house any time they want they've done it before. its unlikely but just about as unlikely as owning a home saving you from "hypothetical" math.
Your best guess about how your investments will increase are "hypothetical" because the market is not a sure thing ... sure, you're likely to win, but that's not a sure thing. I'm sure you knew some people who were nearing retirement who were hurt pretty badly by the market around 2008-2009. Had those people had their money invested in a house, they'd still have had the house regardless of the downturn. Plenty of people have chosen poor investments or have had their investments reduced by fees.
And again, having grown up with financial insecurity, all the math in the world doesn't matter when it comes to my house.
It's a security thing; if you weren't a child who's gone through your closet picking what you'll take /what you'll be forced to abandon, you may not get it. If you weren't a child who was terrified of being sent away to live with relatives who could afford to feed you, you may not understand the importance of knowing your house is your own. If you haven't stuffed cardboard into your shoes because you have holes in the soles, if you haven't split a bottle of antibiotics with your brother, if you haven't been forced to give away your kitten because your family can't feed it ... the list could go on ... you may not understand the security and control that comes with knowing your house is your own.
To be fair, the government
can't just "take your house". They did take a bit of our farm for a road a decade or so ago, and it was a long, drawn-out process. They had to go through many steps to make it happen, and they had to pay for it. We demanded more than their initial offer, and they ended up being force to pay it.
Before you worry too much about me, know that my paid-for house makes up not quite 5% of my total financial worth. My total real estate holdings total almost 20%. It's quite possible to have a paid-for house AND be solidly diversified.