This preserves most state laws.
If a right is fundamental, it cannot be taxed or subjected to the equivalent of a poll tax. Here's a great answer to a question about this issue to some future Court hearing oral arguments: Your Honors, my client views the fee charged to be the equivalent of paying a fee to the govenment in order to purchase a bible, or to attend worship services. They should be a no-go. Would my opponent claim that this provision allows the government to compile lists of churhgoers, to charge them a fee for registering and to make them wait for a permit before they actually attend church. THAT is what gun registration does, and THAT is why this practice should be overturned.
Watch, they will soon make insurance mandatory for gun owners, and to my mind if it's mandatory it's a tax! Or some kindred form of govt theft.
I personally don’t think a fundamental right can be assigned a fee, a tax, or a license.
The Supremes walked a fine line here, wishing to NOT overturn state laws.
Your point is very valid, and something like that may be the basis of another Supremes case.