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.
When constructing a block, miners will choose the highest fee-rate transactions to be included (measured in sats/vbyte), such that they will gain the largest reward for each new block they find.
So the answer to your question entirely depends on how much demand there is for blockspace in the future. As the technologies concerning fee-estimation develop further, we may expect less volatility in fee rates, but it is unclear how low the lowest fee rate will be in the future.
Over the last few years, the network has seen periods of high fee-rates, and then periods of low fee-rates. During the less congested, low fee-rate periods, it is possible to confirm transactions with fee-rates of 1sat/vbyte.
If demand increases in the future, then we may see a new floor for the fee-rate develop, at some level higher than 1 sat/vbyte. How how the new minimum rate is, and how long the new minimum lasts will depend entirely on the usage of the network. All else equal, more demand = higher fees.
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?
A savvy merchant wouldn't hand over a coffee if you broadcast a transaction that pays fees far below what would be reasonably expected to be confirmed in the ~near future. More likely, the merchant would accept payments for small items like a coffee using a technology like the lightning network, or perhaps a sidechain that is more amenable to low-value payments.
It is also possible to create a transaction which pays zero fees, but the network's nodes will generally not relay such transactions (as an anti spam measure). However, if you are a miner (or an acquaintance of one), then you can have a zero fee transaction included in a new block, without having to broadcast it to the network at all.