It's a bit harder. And in absolute terms, generally the natural people are usually only, say, 200-225lbs at 6 feet or so (at the top level, even then people that are that big are accused of juicing...) while the steroid people are like 300lbs at the top level. HOWEVER, what steroids allows a normal person to do is, do really crappy training, eat crap and drink, get 4 hours sleep, and still be at the 200-225lbs "jacked" level without really putting a whole lot of effort into it. Whereas someone doing it naturally will have to put actual effort into it, and make it into an actual lifestyle choice, not just shoot a needle up, go to the gym, eat McDonalds and drink some protein shakes, and then go clubbing.
So it's POSSIBLE to get to a high level without steroids, but it's way harder. And at the absolute level in all athletics (I guess bodybuilding is athletic, lol?) steroid users will generally beat non-steroid users. That's why in weightlifting for example, they had to redo the weight classes. All the old records were set with drugs. Now (supposedly) there's less doping, but it is kinda crappy to know if you set out to do something like that, that there's a high chance you'll never get to the absolute highest level without drugs, and that someone on drugs will probably match or exceed you while probably doing less work. Exceptions exist, but as a generality, drugs are what's required to succeed.
Anyway, yes, it's possible to do things without drugs...
Actually to be fair to the ye olden time strongmen, some of them supposedly used cocaine to cut fat.
Drugs, it's where it's at.