For the winners it can be a very different race. Even at the front of the AG it’s pretty much an individual TT but for the Pros it can be much more of a variable effort. The drafting benefit even at 10-12m is well worth having so staying in a pace line can be worth burning a few matches to stay in it.
If you look a races like Hawaii where there are a lot of relatively evenly matched athletes the pace line can be 20 long and with the rules on drafting meaning that if you’re at the back you can’t just overtake one rider and slot in, you have to overtake the whole line in one shot. That might take a 5-10 minute hard effort in some race situations.
Add into that the effect where you can’t enter the draft zone without overtaking - everybody slows as the front rider hits the bottom of a climb, each rider has to decelerate to prevent a penalty and all of a sudden the guy at the back of the group has to slow dramatically and then accelerate hard to maintain contact with the group. The pro races can be very different to the AG race in many ways so a comparison isn’t necessarily useful.
For the Pros at the very front of the race, off the front of the main Pro pack, the race may be more like the AG race… they’re just faster! The power duration curve is time based so the faster you ride, the higher percentage of CP you can manage. The Pro’s may be riding at 80%+ of threshold, but that’s what they can hold for just over 4 hours and still run. If they were riding for 6 hours the percentage would obviously be lower. Essentially there is little difference between the Pros and the rest of us aside from the fact that they are just better. They have a higher threshold and can hold a higher percentage of it for longer.
The other side of Pro racing is just that - it is how they make their living. Unlike us for whom achieving our race goals may be to race at an even pace, the Pros may well need to be where the race is at, and sometimes that may mean gambling early on to stay with the lead group, which may or may not work on the day. Sometimes, especially in the bigger races, it may be a case of going as hard as you can until you go bang and the last man or woman standing wins. For some it’s a gamble worth taking to be in with a shot of a good placing.