Some people can make a living doing something they enjoy. "Success" is not fame, and vice versa (they are wholly orthogonal to each other), and I remember reading an interview with a member of Canadian group Saga, who in the US had like 1 top 40 hit in the early 80s and a few more minor ones in their home country, but ultimately they sell a few thousand records a year, and tour regularly in two "big" markets for them : Puerto Rico and Germany, and they seem to make roughly a middle class lifestyle doing so.

Beats being an accountant or urologist I suppose.

I suspect there's a similar vibe for cover band folks.