The block subsidy expires 99% by 2040 and 100% expired by 2140. I have no idea what the tx fee will be after that, but let’s take your guess of $100/tx as a bas

The block subsidy expires 99% by 2040 and 100% expired by 2140. I have no idea what the tx fee will be after that, but let’s take your guess of $100/tx as a baseline. Whatever the fee - whether $1/tx as it is today or $100/tx, once the fee is paid, the Bitcoin funds on that address are secured for no additional charge until such time as the funds are moved to another address via an on-chain transaction. So you could be paying $100 to store $1000 or $1 million in Bitcoin for 1 day or 20 years for the same fixed price. Seems like a good deal to me.