It would be enough for vast majority of people, but the problem is that if you suddenly get $5M, be it through inheritance or lottery or any sort of "sudden enrichment event", most people just go and spend it all in few years. There's a huge temptation to buy your way into a higher social bracket, but it only works if you have an income matching that bracket, otherwise that pot of money is going to run out sooner or later.
There was a TV show once, that interviewed rich people. Some lottery winners, some who made company money, etc.
One of the lottery winners made 2m and started his own business, some car workshop stuff and went bankrupt 2 years later.
A couple made ... I don't now >10m and the first time they visited them, they told that they will keep working in their normal jobs because they like them. Half a year later, when they got interviewed, they both quit their jobs and were building a house and the guy was always talking about that he fears it wouldn't get big enough.
One guy made big money by renting out building equipment, he had a big nice house which he let build completely to his wishes, but lost everything to bad investment. They even visited his old house and the new owner let the camera team in.
The new owner also said, if he would get rich again, he would sell him his house back, which I found kinda nice. But I always have the feeling that people who got rich are simply lucky, even if they didn't get it through the lottery. So he probably knew that guy wouldn't get rich in this life again.
