Freedom from stuff, freedom from excess space, freedom of time, freedom from cleaning. All of these things take time, energy, money, and resources, going smaller means these demands are reduced drastically. You then have freedom to do what you want, what is important, what really matters in your life.
McMansions cost allot of money, I am sure you have noticed. The average US house costs around $265,000. But it doesn’t stop there! In order for you to get into that big house, you have to get a mortgage, which by the time you pay for it; it will cost you two to three times that, so roughly $800,000. Then add maintenance, insurance, furnishing such a large space, cleaning products, etc.
Then there is the risk that comes with a mortgage, even with buying a house that is conservative for your income, even if you save for 3-6 months of pay in case you get laid off (which 95% of Americans don’t budget for), you could still lose your home after paying it off for 28 out of the 30 years you have on it. So factor the cost, plus risk, then consider the opportunity cost, you could be well in the hole close to 1.5 million dollars and then be left homeless.