This is the problem with permissioned transactions which cryptocurrencies remove. The only thing missing is adoption.
With the fees and issues I don't understand why the porn business isn't pushing harder for cryptocurrency use on their sites. There's huge amount of money to be saved here.
And lastly, Bitcoin fees currently aren't large and you can get a confirmation with a few cents fee. That might stop being so if it becomes too popular again, but if off chain solutions like Lightning Network pan out, then that'd be sorted out.
Further 2 exchange fees sit on of those 3 coin transactions.
In theory you can have an exchange handle all 5 of these transactions, but then your using the exchanges book's not a block chain.