There won't be a last block.
Discussion
I misspoke there, there will never be a last block as long as transactions need to be processed. I meant to say there will not be a last bitcoin mined. A lot of people say that “the last bitcoin will be mined in 2140” which isn’t true. More decimal places will be added and units lower than Satoshis will be the reward for mining a block.
Never looked at it from that perspectieven. Not sure if I agree, but certainly a tantalizing thought experiment. Will think about it! Thanks for the perspective!
Yeah so the point of my OP was to say that it won’t even be a choice of whether to add more decimal places. Once bitcoin is valued high enough, we will need more divisibility to pay for some things. Example: if 1 sat = $1 and the price of gum in dollar terms is $2.50, we need smaller units than satoshis to cover the $0.50 portion. I think this is already possible on lightning though since there’s mSats.