It's their job to be flexible and powerful for hours at a time. Pelvic rotation, setback, stem length, and frame geometry all come into play in this situation. They do run smaller frames than amateurs of the same height, but they also know and are physically able to get and ideal pelvic tilt for power/efficiency/stamina. I think if you asked Chris Hoy whether lowering the saddle yields a faster cadence, you might get a "No." This guy: https://www.youtube.com/watch?v=sVbwngNoHm0
seems to have a bit of a bounce before his cadence smooths out, he also doesn't have an especially low seat height.

I would bet that if you normally ride a 56 and went out on a 52 with a super long stem, your position would look like a tour guy, too.

I ride with a guy that has 7 inches of saddle to bar drop. it's the only way hes comfortable but just looking at it hurts my neck

Is the smaller bike frame also the reason for the long stem neck some riders have?

Yup. I don't know how some riders do it without getting a stiff neck afterwards.

I ride with a pretty decent drop and I find its all about the breathe......if you are diaphramatic breathing the core expansion seems to kind of inflate and deflate in a way that mitigates what would normally be a constant strain on your back

Lower saddles hurt my knees...

I think they do it to make themselves look like giants. They probably are wearing jerseys that are too small as well so that they look bigger on tv.

yep, gotta make up for the shorter top tube