In the future, if I pay a coffee with a very low fee, will it ever be paid? So this is the thing, I am just learning about feedrates and how the miners pick their transactions with higher fees, so they can get more money. But, what will happen in the future when people pay really small things in the daily basis and the fees are insignificant, does this mean that I would get my coffee but it will be never paid?
No, ofc not.

In future, if the fees are insignificant, there will be a lot of transactions and miners will get the proper rewards for their work by all those small fees together.

New blocks are coming with new transactions every 10 minutes. Any transaction with fee superior to 1sat/byte will eventually gets confirmed.