Forgive me for being harsh:

Why is there no "pen-test" phase to any crytocurrency which hits the market.

So, let me understand; you're ostensibly smart enough to (perhaps as a body of contributors, even) develop a cryptocurrency offering - yet youre also fucking stupid enough to not have same/wider network of ppl attempt to hack the fuck out of your plan?

Does this already occur? or some savant comes and owns them?

We have fucking HIPPA FFS and the compliance systems for something as trivial as my stupid name.

so; ELI5: WTF are currencies doing/not-doing which allow for such hacks (1) and allow for exploits to go unseen (2)