Exactly. I find it funny all these Sherdoggers think BJ is above doing steriods when he's done stuff way worse than them in his life. There's a good chance he probably took them at some point. Who expected Anderson Silva or Jon Jones to pop? Neither are exactly built, and there are steriods that help out in other areas than just muscle building.
It wasn't just lack of work ethic either, it was mostly Penn not being a natural athlete and the sport just passing him by too quickly. He was primarily a BJJ guy with good takedown defense who started to get good at boxing and relied too heavily on his hands. He got away with it for a while because he rarely fought well rounded wrestlers with hands. There weren't that many wrestlers at LW at the time, they were all at WW. And when he did, he lost (GSP, Frankie, Fitch, etc.). Sherk was a good win, but Sherk also didn't shoot for any takedowns against BJ and was relying way too much on his striking at the time which wasn't that great. And Matt Hughes was another good win, but Hughes was a wrestler without any hands, which was a good matchup for BJ on the ground or standing. Others like Serra, Renzo, Stevenson, and Sanchez weren't wrestlers, they were either BJJ guys, strikers, or a mix of the two.
Not trying to crap on him, but he'd get destroyed in either the current 145 or 155 divisions where there are tons of wrestlers with good striking. Just look at the builds of all the current fighters in those divisions. Even the bottom tier ones are still in shape and can easily go 3 rounds. BJ really never had great cardio, strength, or heart unless he was dominating. And the guys today have far better wrestling then any of the people he went against with the exception of GSP. On paper, Frankie, Oliveira, Benson Henderson, and Khabib all have far better records then him and have fought way more diverse competition.
His "peak" was a pretty short window too. He's kind of like Cain Velasquez where people overrate him based on "potential" and how dominant he was within a short window against a limited amount of fighters.