There are different waves of investors from the true believers who mined because the idea was powerful to the mt gox crowd, coinbase newbies, wall street / hedge fund crowd. Each group has a different reason. The latest groups are looking to make money and the earlier adopters have moved to a less popular more ideological coins with advantages over bitcoin.
Mafia no.. something else yes.
The big example of this would be the 2008 banking crisis where CDO's were bought and sold by multiple banks, but ended up being worth less than the pieces of paper they were printed on -- even though the banking industry should have known this were the case.
Once it was known, they sought to protect themselves first -- "Too big to fail", TARP were common terms of the time.
See: https://en.wikipedia.org/wiki/Apalachin_meeting
not quite suing, but it was a diplomatic way of resolving disputes and preventing them.
Ponzi schemes don't have to run by single individuals, but perhaps by multi-person organizations like the mafia. The mob was the reason the RICO laws came to be.
And undoubtedly, the mafia organizations would collaborate to break up their crime into regions. Mafia group A would take the West, etc. Since they're a criminal organization, anti-trust laws were meaningless. There wasn't a requirement that the different mob bosses had to compete with each other.