In my mind they are very different. And BTC's and ETH's are very similar. In open source crypto currency projects monetary policy is held by a "social contract"
https://vitalik.ca/general/2021/03/23/legitimacy.html
BTC's 21M hard cap, is not really that hard, it can actually be modified by a soft fork (according to Andreas Antonoupolos). In any event, both BTC's 21M 'hard' cap and ETH's minimum viable issuance they are held by a social contract. If people feel cheated out of that contract (say, because ETH's all of the sudden start to print more and more ETH) they are not going to sit by, they can fork the code and remove all that issuance and continue the coin.
But more importantly, both BTC and ETH dont have that much incentive to print coins and drop their value. Most developers on both coins own a lot of that coin and want to see it suceed. Central banks usually print a lot to accomodate the problems from the fallout of debt crisis, they also are appointed by people that want to be reelected and printing is a way to get there. In crypto currency, printing is a fast way to lost adoption and piss people off. So I see no reason why the Ethereum community would starting printing tons of ETH all of the sudden. And security wise, its probably a better choice rather than choosing the inflation rate and trying letting time tell you whether that is secure or not.
BUT
I do accept that BTC's story in a world of financial repression (cash is trash), flight from fiat, and currency debasement, BTC's is simpler, easier to understand and a more seductive story. And the problems associated with that are 10+ years in the future. So BTC's seems to have an advantage as a Store of Value that is hard for ETH to break
Valid points.
What comes to mind is that PoS is untested in an adversarial environment. It could also be argued that ETH had not had the same ‘fair launch’ as BTC.
The system would allow large capital to have a greater voice.
Like this recent ‘soft rug’, there are different interpretations of the social contract.