I get the whole scaling issue and yes it is an issue but I am not in Bitcoin because I care about how they scale but how it scales my bank balance. Like you I have a few bets on crazy interest rates but probably a way smaller percentage of my portfolio since those returns rely on timings, getting lets say a 30% APR depends on liquidity and the order volume to get in and out of that and I don't have time to play that game.
Most of these alts hard caps don't mean dick anyway so they can keep inflating it away to produce returns. BTC can't do that, too many HODL"rs would revolt so the interest rate is highly elastic, if you look at these sites we're using like BlockFI they're scalping a premium and giving an okay return but if you drop into the P2P market like HODLHODL you can get easily 17% APR on your Bitcoin
For me I am keen to see how elastic interest rates become as those without Bitcoin need to encourage removal from cold storage