Exactly! Thankfully so long as the presence of a robust market for implicit fees exists and such implicit fees outweigh what could be obtained by this strange permissioned explicit fee stuff, then we hopefully have nothing to worry about.
For an (albeit hopefully very unlikely!) world where blocks are completely full most of the time and where the subsidy + implicit_fees is much less than the revenue available from these (permissioned) explicit_fees, I merely wanted to raise it here as a possible edge case with a potential adverse side-effect.