[acoard]

> My next question is are there downsides to proof-of-stake, and why has bitcoin not moved towards it?

There are minor downsides in theory. Proof-of-stake is a bit less "democratic" and gives more voting share to those who have more money, vs. just are mining. In practice, proof-of-stake coins seem to be doing fine. The main one here is Ethereum.

The main reason Bitcoin hasn't is due to inertia and the interest for miners (who do proof-of-work) to use their democratic power to keep bitcoin invested in proof-of-work.

[schlauerfox]

Proof-of-stake ruins it's security with a rich get richer endgame where the stakers concentrate until it's not distributed enough and one entity or group can collude and control the system and there's no way to exit that state.

[HPsquared]

Wouldn't any such holder want to avoid this condition developing as it would devalue the whole currency?

[keyringlight]

Wasn't there a few times when one of the large cryptocurriencies were almost under control of large mining pools where their combined computation would have gone over half? That seems like another "who has more money".

[Sohcahtoa82]

With Proof-of-Work, "rich get richer" is a side effect.

With Proof-of-Stake, "rich get richer" is essentially coded into law.