Damn, economy is complex. I've been thinking for a while and i'm not any closer to an anwser than at the beginning.
I'm not sure how much inflation matters. On one hand, intuitively, I'd say if something is generated out of thin air, it should eventually become worthless. On the other hand, fiat is practically generated out of thin air and yet kinda-sorta works.
But fiat is also unique in the sense that it doesn't really depend on exchange rates; your salary is fiat, the grocery store takes fiat, at this point people believe in it so strongly it's just this ubiquitous IOU representation. But when you have a less popular, in everyday life practically useless token, exchange rates matter. And they are sensitive to volume.
It would be interesting to see how much BTC is mined vs how much steem tokens are generated per unit of time compared to the total available volume though.
And to address your point about BTC: I don't think mining has to be profitable. As long as it is, of course you will see huge farms consuming a lot of electricity for profit. Eventually, I could see users and merchants running single nodes in their own interest to keep the network running, breaking even from transaction fees or probably even at a loss. That would be the ultimate decentralization.
Btw thanks, thanks to you I'm even more confused now :/