I could argue that 1+1 is a proof. Maths solutions are always proofs.
What we usually mean by a solution is a method or mechanism.
Many people prefer stools or beanbags. And when you describe people reaching the same conclusion. I would call that a consensus rather than a realisation.
On your last point we seem to have different premises.
I don't think filecoin or Nexo are good investments. But I do think they're interesting ideas.
Not every use of blockchain will make money, but that isn't the only reason to use a system.
Gold isn't only used as measure of value. It has even more valuable scientific uses.
Nano materials will get cheaper and cheaper but their utility is beyond monetary value.