We have transactions fees, to avoid creating tons of transactions and increase the blockchain size to a extreme amount.
Those transactions fees are sent to the next user who is the miner.
How would the economy of a coin would change if instead of sending the transaction fee to be mined, the transaction fee was frozen and 1 year after it it would be sent back to the wallet. The user wont lose that money, but still can't keep making tons and tons of transactions to spam the blockchain.
I am referring to any coin in existence here and not just bitcoin. Majority of cryptos have finite supply. So your proposition can work for a finite period of time only. But once all coins are mined, who will keep the network running without a reward? It wouldn't make sense to any of the miners to keep running their nodes with zero rewards. So even if small, but still some percentage of transaction fees needs to go to the miners to keep network running for longer time. No one really like to provide free service!