It is that simple, but I don't personally know anyone that does this, hence not many people have a decent bench. I only bench what I consider light, and I don't really do it often and I can still do 120kg for reps any day of the week, imagine where I would be if I was serious and actually concentrated on benching and increasing my numbers.
Arnie did, so he had a decent bench.
Anyone that trains as hard as what he did will see results, most people don't, so they don't see results.