This sounds off to me. I was able to save ~20k EUR / year while on a 40k/year PhD salary in Austria. I was living a decent livestyle (intercontinental yearly vacations, taking on cost-of-living expenses for my girlfriend, ...), yet I was far from the upper 5 % of the population, and living in an expensive-ish town (the gentrified/expensive area of Berlin i now live in has roughtlye the same overall CoL). So I am assuming your problems come down to varying definitions of "decent lifestyle".