Why do the pro riders have their saddles so far forward?

[Foghat]

I have mine as far back as it'll go, & have even considered filing the seat-clamps

Me too.

For all my custom-built frames, I have always specified 72-degree seat angle so I can get the saddle back far enough.

My knees never feel right if I'm not a long way back, and I determined all this when Bernard Hinault wrote his book on road racing technique - he explained how his performances, stability and comfort improved when he moved his saddle back by 26mm to an 80mm setback (not all in one go). The book's section on positioning is excellent, and I put it to good use.

These riders who position their saddles so far forward just look so wrong for endurance road cycling - and especially for bad road surfaces and descending. Hinault's side-on before and after photographs demonstrate this very well.