But no one would get rich quick, so it would probably never take off in the first place.
Right now we're seeing the tip of the iceberg of potential cryptocurrencies. Pretty much only token-based (ie. non-ledger) based currencies, where we need global BFT consensus to track the current position of every single coin. This is crazy. And, as it turns out, unnecessary (see: Holochain).
When the iceberg capsizes (as Git capsized the CASE industry), globally consistent ledger-based value-stable currencies based on peer-to-peer co-signed personal blockchains will supplant these unnecessary globally consistent token based ... things. (Do I really care that you just slid a nickel across the table to someone? Nope). Same with crazy Turing-complete globally consistent VMs implementing Smart Contract languages. Not necessary.
You are correct -- value-stable currencies won't have anyone getting rich quick. But, when every sub-saharan goat herder and neighbourhood kid with a collection of trading cards can independently monetize his/her wealth into a value-stable currency, we'll see the face ripped off of the global Fiat monetary systems...