I don’t have a gas grill, but to follow up on prtrumpet’s question; what about ceramic briquettes? Do they have similar drawbacks?
I had a CharBroil that used ceramic briquettes, and they have the same problems with grease build-up causing flare-ups as lava rocks do. They can be cleaned by covering them with heavy-duty foil and turning on the burners for a while. I believe they last longer than lava rocks. These are what was used before the flaforizer bars were invented, so the rocks or briquettes are definitely old technology.