We’ve been discussing this topic extensively in the 80/20 polarized topic and the more recent ‘sweet spot or sour spot’ topic.
https://www.trainerroad.com/forumt/quality-over-quantity-vs-80-20-or-chad-vs-matt/
https://www.trainerroad.com/forumt/sweet-spot-or-sour-spot/
I do think people can get tripped up in their training. It should be dose and response but people don’t wait for the response. They don’t like to rest.
If you do a lot of Z2 you can ride more frequently with less rest. If you do a lot of SST and threshold then you definitely need to have rest days - probably 3 full days off per week. I have a feeling that people short cut that and also ride outside.
People also get into the more is better mentality. If 2x20 SST if great, then doing it twice a week is even better, and three times a week is even better, etc.
And then age factors in… I’m 53 and need more rest than a youngster. I cooked myself doing base miles and then needed a full rest week. I progressed from 6 hours to 13 hours over 7 weeks. Last week was a 6 hour easy week. In the end it was probably great for my aerobic fitness but I was really dragging towards the end. I’m coming around to thinking about shorter blocks, more rest and more adaptation.