It seems to me that bitcoin will have a problem in becoming mainstream because it will feel more expensive to use than standard fiat.
In the case of Bitcoin, it seems to me that the transaction fee is always worn by the buyer and that would make it simply feel more expensive.
bitcoin has been around for about 9 years now and in all this time except a couple of months (which is less than 5% of its lifetime) the fees have been a couple of US cents.
In the current fiat system, you don't have to pay a fee to use it (in most cases), so it means there is a lack of incentive to use bitcoin for everyday transactions.
you don't see the fees you pay with fiat system, that is different. when you purchase with credit cards,... the vendor pays some fees, to cover that expense they add it to the value of their goods they are selling you and you don't see it because it is not a separate thing, it looks like the real value of what you are buying where in fact a part of it is to cover the "fees".