Bitcoin mining isn't supposed to last forever, otherwise it would look a very bad investment and probably a ponzi scheme. Every precious thing is limited in supply and that is what makes this thing valuable. That seems very logical to me. No way to change the fact this opportunity won't be available for kids of future generation kids as gold rush wasn't available since my grandfather generation more or less.
But don't worry, if technology keeps advancing and the humanity achieves even higher progress levels these kids will have better opportunities and life quality during their lifetime.