The block reward will be substantial enough for decades to come, and transaction fees have already passed what the block reward will be in 30 years. There is no logical argument that goes, “we need spam so miners remain profitable.”
https://primal.net/e/nevent1qqsplg3rdj456y7hmgh3nwj4u2knmp0z3syu0h3y32nuqhffu9ud3gqfk468l