Anyone who's started late like you and I have the same sort of "what if" regrets about not starting sooner. You'll see a lot of folk on the forum have the exact same issue of being unable to convince younger lifters, older lifters, women, men, collegiate-level athletes, and everyone in between that SS works better than the bodypart-a-day split they're on.
The 'problem' with the SS model is that it's efficient. There's no bullshit if YDTP - and even when YNDTP it's still very efficient and will get you stronger faster than you thought possible. People have been told for so long by purported fitness and health experts that this is supposed to be a complex process involving a lot of expensive machines doing isolations and core work, taking many hours of time. Add to this medical professionals saying idiotic things like "Squats are bad for the knees, deadlifts are bad for the back," and so on, and you get what we have now.
There's a lot of bullshit out there, and far too many people believe it.