I can't believe it has to be said, but Peloton will be just fine even with Apple coming out with #Fitnessplus.
Why? The same reason an iPad/iPhone/MacBook is good. The close integration of hardware and software. Peloton is a first class experience. An Apple Watch is not a bike.
It's hard to cheer for Peloton, but you are likely right but I believe their model works because they decoupled their classes from the bike and you can DYI from home.