It's because fees aren't calculated by the amount transacted, but by the size of the transaction. The more outputs you spend the greater the fee will be. Remember, the miner just includes data in a block and is incentivized to mine what pays more, regardless of the amount the people transact.
Also bitcoin can never become proof of stake unlike other coins,so where does this leave us ?
What does that have to do with the transaction fees?
Also at the same time there are other options that can be used you can always use wallets like samourai where you can choose your transaction fee and at the same time you can also use the lightning network, which does mean that you can use it effectively well in case of small business requiring small transactions as well. Plus the data is too broad to consider any option as well. The price of Bitcoin keeps on changing which does mean that the price of transaction fee would change as well making it more profitable in certain circumstances and at the same time during the high prices the fee would be extensively high, therefore you cannot just analyse it in any way, we need more effective studies.