They will raise the transaction fees so high that your BTC isn't even enough to pay the transaction fee, so it will be impossible for you to spend them on chain.
What might that threshold be - 10 BTC, 100, 1000...?
At the point where there may be only a few million Bitcoin-holding entities, wouldn't anonymity be broken due to blockchain analysis methods combined with the reduced user base? Or would agreements be adhered to at the top, creating a glass ceiling barrier to the Bitcoin billionaire gentleman's club?