It's been a while since I read TMND, but I thought the premise of the book wasn't specifically about depravation to accumulate money for accumulation's sake, but more about turtle v. hare...
Many small business owners "end up" millionaires by building their businesses over the years, wherein eventually they own some commercial real estate, own the 60s vintage ranch they've lived in since the 60s, drive a (beater) pickup rather than a luxury car, etc.
One uncle fit that description. Owned real estate associated with his electrical supply business, of which there are now three stores. Aunt drove a nice US-built Caddy or Lincoln, but he drove an old Dodge pickup. Lived in a 60s-vintage home, long paid for.
A couple of my cousins also qualify. A g-uncle started small, in dairy and grain farming. The boys farmed, and also helped run a farm implement sales and service outlet. In the past year or two, they've sold a chunk of the old homestead for a significant profit, and still help sons from the next generation do the planting and harvesting, but have mostly retired as snowbirds. Still drive pickups.
It's easy to accumulate assets when you're making six/seven figures, or should be, but the takeaway for me was that many of the millionaires/wealthy aren't high-powered CEOs, lawyers, or celebrities, but relatively ordinary people, who, after a lifetime of work, now own a chunk of commercial real estate, or farmland, or a bunch or rentals...