Airline domestic first class isn’t a marker of wealth, since a large subset of passengers able to pay for air travel can pay for first class as well as it often isn’t that much more. But it hasn’t really ever been a marker of wealth.
Twenty years ago 90% of seats up front were going to upgrades, which frequently meant business travelers who weren’t poor by any stretch but often in the middle rungs of the corporate ladder. Who is flying up front has changed a bit, especially with managed business travel still down, but it hasn’t matched the mythology of the product in decades.