1. Lubricants are much better
2. Clincher tire technology challenging tubular performance
3. Wheels are much faster and more reliable
4. Apparel is much more comfortable and aero
5. Bikes are much lighter (ti and carbon). 22# used to be a good road bike, now it is 15#
6. Gearing ranges allows one set of wheels (5 speed FW vs 11s cassettes)
7. Sealed bearings.....remember tearing down pedal bearings every few weeks riding in the rain?
8 I suppose nothing is better than a 66-42.
To me, these were all large advances....
Most important advance for safety is the easy availability everywhere of low priced, battery powered LED lights and blinkies for front illumination and rear visibility.