Because like the triumvirate of off roading accessories not too long ago, (hi-lift jack, Optima Battery, and K&N air filter) the swing out tire carrier had to be run if you ran anything other than the stock tire and rim and that is due to the extensions being sold that just trash the tailgate, folks that move them (the spare) up without making sure they are done correctly and then the damage gets shown without a clear understanding of what actually caused it.
It wasn't "run" for 13 years, it was run correctly so the tire didn't move when the gate was closed and it had to be shut with authority to get it closed in order to slightly compress the snubbers.
I've seen quite a few stock rigs with 32's on them and a swing out tire carrier and bumper so the hype exists as does the need to buy accessories and bolt them on.