I don't know what things were like in Dec 2020, as I only got the premium account about 6 months ago.
Prize values have always gone up and down in sync with BTC values as far as I can remember. That's fine and perfectly understandable of course. If a player previously would win 30 Sats, and then the price of BTC doubles next month, then the same player should then win 15 Sats next time around, that makes perfect sense to me.
But the thing that I find strange is the changing of the actual fundamentals, the odds for the prizes. If it's true that the actual odds have changed, then spinning is obviously not as much fun as before. As an example, a few days ago, I did about 120 spins, and every single result was the same prize, either the lowest sats, or the lowest lott or the lowest RP prize. I can't say that spinning the wheel is very exciting when every result was the same.
I have zero issues with prize values decreasing or increasing in proportion to the value of BTC, but if the odds and fundamentals have been changed, then that is the only thing that I find to be strange, because those wouldn't be the same odds that were in effect when I bought the extra spins via the premium membership.