I thought this was interesting because actual watts to be gained/lost are hardly ever quantified. I mean, if I go from 6-8 hours per week to 12-15, what’s it going to do for me? It’s always hard to know.
20 minute power: 400W to 370W
5.5w/kg to 4.6w/kg
loss of durability
I saw this thumbnail a few times on YT and ignored it. Just watched this clip and I’m not really sure I see the point he is trying to make… This content doesn’t really seem to say much other than, when you do less hours, you lose some performance, but maybe not as much as you think.
*If you have years of high level endurance training experience (and likely very good genetics)
My takeaway was more like, “While I lost some fitness and stopped reaching the podium in Cat 1 races, I still have the ability to perform in Cat 1 thanks to years of training and racing experience, but I gained so much more balance and happiness in my personal life”.
I think he was trying to quantify the volume trade-off and add some data.
Another point was that you can’t make up the lack of volume with quality. Some platforms over the years have suggested that you could. 
I thought it was interesting mostly because he’s put some numbers behind it. Ai can’t tell us how much FTP and/or durability (which most amateurs don’t measure) one could gain by upping volume. What does one get going from 6 to 8 hours? 10 hours? 12? 15? What if I do one 5 hour ride every other week? Nobody knows. We only know that more is better.
I’m guessing that Roadman is still on his slow fitness decline. He’s still hanging on with the years of training in his legs.
I thought his fitness decline was fairly steep. He went from cat 1 podiums to cat 2 pack fodder.
I think the point is that 12 hours a week is too much and it’s going to destroy your personal life and relationships. I agree 100% and think that everyone I race against should only train 6 hours per week (don’t worry if that doesn’t get you 4.6 w/kg though).