Treat this as a harmless question.
First of all I don't think your question is harmful but rather a nice one.Secondly Bitcoin mining hash rate drops after every halving this is to help slow down mining rate . Bitcoin has a total supply of 21millon of which about 90+ percent has been mined already and the remaining supply would not even been mined totally any time soon.However if the entire supply is mined, miners will now have to focus on rewards they get from confirming transactions.
Also transaction fees may increase in the future when the total supply is mined but future fees is not only depent on the miners as ordinals,forks and other factors have a great role also to play in the future.