Roids makes a huge difference and anyone who says otherwise has no idea what they are talking about. There was a study done on men who had lifting experience where they put them on various doses of testosterone for 5 months and had them NOT lift at all. The men that were taking dosages that took their testosterone levels beyond the natural range ended up gaining muscle mass, of course gaining more with the higher dosage. I personally wouldn't touch it because of the health effects, particularly on your cardiovascular system, but something that many seem to overlook is that it completely shuts down your own hormone production, your testicles shrink and you become sterile. You are supposed to blast and cruise, where you come off for a period before going on again, but a lot of guys don't do this and they literally go years without ever being off. There's always the chance that you could be on TRT for the rest of your life, which is not something that I would be interested in.
As for the celebrities, there's a reason many of these guys are able to get these drastic physique changes in relatively short periods of time. Aside from underweight noobs and teenagers, it's impossible to see changes like this without steroids. If you are natural it can take years of eating really well, decent training and good genetics to be strong, fit and look good where people will actually be impressed. I've been into this for just about my entire adult life, at 6'4" with really good genetics and my overall lifestyle is heavily based on this (no drinking, drugs, smoking, etc.). Most people are not going to be able or willing to put that amount of time and consistent effort into something like this, which is why many resort to drugs in the first place.
Testosterone: Real-World Data - T NATION (t-nation.com)
Anabolic Steroids: A Survey of 2,385 Men - T NATION (t-nation.com)