I think you make a mistake here. If bitcoin prices do rise, then the fee in USD will also rise, because the fee is not calculated in USD but it is calculated in Bitcoin. Since the value of your bitcoin holdings will also rise this will not affect you at all.

What you can also check is the transaction prices and how they changed in the past. There were already several halvings and still the transaction price is pretty low. This is also because the bitcoin payment system is constantly improved. So in my opinion you should not worry about that.