But you're getting to the genetic freak stage. A round ball travelling at 90+ mph and a round bat. You can either do it or you can't. It's like the SVJ. You can improve it a little with the right work, but you're not going to go from ok to great at it from strength. Hitting a ball moving that fast with a round piece of wood in such a way that it consistently travels over 300 feet in the air is not something you make yourself do better by getting stronger. It can be a game changer if you can make that contact, but considering 360 and 420 usually have the same result(HR), you're not looking to the added strength to hit it farther, since you can already do that. You're looking to it to keep you in games you might otherwise have had to sit out.
The point is that the guys you are talking about already hit it far enough. As I stated, the one exception was infielders who never could hit home runs. *They* benefited greatly from PEDs, because they had warning track power that suddenly the couple extra MPH of bat speed gave them the extra oomph. But that occurs far less often than popular theory thinks. The number of balls that would have gone out that didn't due to a couple MPH is far smaller than balls affected by wind. The big guys can hit it further to begin with. What difference does it make if Giancarlo Stanton hits it 450 instead of 430? It's a home run either way.
Sure you can get stronger without PEDs. But as Rip himself says, you need to sleep, recover and eat properly for the adaptations to take hold. How does a guy do that when he has a game every night, with batting practice beforehand, etc? The PEDs allowed them to lift and recover and still play, while not getting hurt. *That's* why guys took them. Over a season, it's been shown that even the worst players, with 600 PAs, are going to do certain things. They are likely to hit 8-10 HRs, get walked a number of times, and get 125 or so hits. (Actual numbers may be slightly different, but illustrate the point). The best guys, well, another 40-50 PAs can lead to some serious additional production.
There are plenty of guys who for one reason or another(media favoritism, the dreaded "eye test", really didn't do it) who aren't suspected of PEDs and put up some real nice numbers. I'm just saying the popular myth that guys took PEDs to hit the ball farther is really not the case. Teams can just move the fences in if they want to. It was about staying the in the lineup far more than hitting it farther.