"NordicTrack says it supports right-to-repair rules. However, because of its equipment’s moving parts, the spokesperson says, it believes that restricting access to its operating system is important for safety. "
The real reason they don't want people using other apps or watching third party videos is because anyone doing that is not spending money on iFit. Or, at least, not as much as they could be. NordicTrack likely discounted these treadmills to squeeze out competitors with the intention of making their money back by locking customers into iFit.
If a few users hack their treadmills, that's not going to hurt NordicTrack's bottom line. If most users are doing it because it's as easy as tapping the screen 10 times, then there's a problem. So, NordicTrack has made it harder to gain admin access. Not impossible. Just harder. More people will go back to spending money on iFit, the determined few will roll up their sleeves, and the business model will be restored.
The problem is that this business model is a bait and switch. When people pay for a treadmill they don't expect to be locked into further monthly payments to unlock its features. It's inherently dishonest, and the victim, aside from users, is the competitor who produces an honest product that's paid for entirely up front and is, hence, more expensive and less competitive.