FTP is important but the ability to access anaerobic sources over and over again is more important to deal with the surges in criteriums in my wheelsucking experience.
CDR might have a modest FTP, sort of like the gas engine in a Prius but the battery reserve component of his is like the top of the line Tesla. Functional Reserve Capacity or W' is just as important if not more.
In Cat 5 races, there is constant action and it is hard to know what break efforts has the chance to stick.
The last Crit I did was a couple years ago, 55-65 year olds. Many of them were Cat 1-2 back in the day. I could not compete with them then or now. There were exactly three moves in the race, including the sprint. After the first Prime, an attack by three at the gutter with no place for others to draft. Two laps of chasing all out. When it ended after we caught, I looked over to fellow at my right elbow and said, "thank GOD" and he said, "No ****". This was the move that many riders got shelled. I made it to the final sprint, which was fine for me.
New racers probably don't realize that if you are off the back, you are done and that you and average Cat 5 must stay in good position and do everything you can as if the race is right there and right now when you start to get out of position or worse start to slip off the back. There is so much going on in Cat 5, I suspect it is hard to tell but the bottomline in my opinion is not to let gaps open no matter the effort it takes because once you are off, you are off and done.
I always enjoy watching CDR's video. I was looking for one to post and then lo and behold, he posted to this thread.