There should be some creative ways that won't be straightforward
The main idea behind it is simple: you post a transaction on-chain, and then, it is possible to refer to that later. Which means, if there is some transaction from 2012, that is confirmed on-chain, which contains R-value, matching your commitment, then it is impossible, to change it now (in 2024), without re-mining all of those blocks, and changing R-value of that signature today.
Note that you don't have to make another payment, just to confirm some message, if you don't want to. It can be outsourced, one transaction is sufficient to confirm all pending commitments, regardless of their size, which means if it would be enforced on the protocol level, then mining pools can just be responsible for that, and provide that kind of service (and it would cost them zero additional on-chain bytes, because commitments could be stored by users, and they could provide just some 256-bit hashes, to be committed).