I see and respect your opinion.
If the point is that "I’m completing my workouts but my FPT went down: (the topic), we have to understand that FTP is a rough number. There’s a lot of variation due to the human nature, environment and technical issues (1-3% margin of error of a PM).
Then, the way FTP is measured is another huge discussion, even the creators of it don’t fully state that testing 20min 95% minus 5min all out to deplete your anaerobic system will give you the gold standard. WKO5 uses mFTP, which for me is a fancy Critical Power model, and if you take the time to watch one of Kusik’s webinars, you’ll see that you have to test every other week - 5sec, then 1 min, 12 min, and so on - in order to have the best ESTIMATE of your FTP (mFTP?)
TR then offers AIFTP, which works reasonably well for most people, especially if you provide good data. With that in mind, we know that FTP isn’t accurate on the dot by any means.
Completing workouts won’t increase your fitness - fitness, not FTP - alone. A few points to understand: Is the person (people?) complaining eating well? Sleeping well? Doing the basic housekeeping? Stress level? It’s hard to tell, but it’s easy to blame the software/product/coach.
I had a coach last year and completed most of my workouts. My FTP went up. However, I burned out so badly that I had to pull the plug on my “A” race. That meant my FTP was roughly corrected assed, but my performance was not even close.
Was it his fault? I don’t think so. I realized later that I was underfueled.
To wrap this up, stating that “a lot of people” are reporting this issue of completing workouts and getting lower FTP numbers is a bit intangible. We don’t know the numbers of TR users to statistically define a sample and then test this sample to check how many people, statistically, aren’t getting the results they expect.