That's great. That is something to be proud of.
My biggest complaint in the times I've listened to him is he ignores opportunity costs. You have paid off two houses and pay cash for cars. If you could have financed those assets at a lower rate than what you could have earned on the money you used to pay off those assets, you would have more money/net worth today than what you have now. For example, my current home financing rate is 2.25%. I can earn more than 2.25% investing that money. So by financing at a low rate I can use money I would have used to pay off the house to make additional money. My car loan is at zero percent, so anything I earn on the money I would have used to pay cash for the car is profit. If you can't finance at a lower rate than what you can earn by investing the money, then you are better off paying off debt than investing. If used correctly, financing is a good tool to build wealth.
Your point is a good one, except it leaves out one thing. Most people absolutely do not have the discipline to invest all the money that they would otherwise pay to a mortgage, and end up spending lots of it on stupid shit where they would’ve been better off just paying off the house in the long run.