I believe TR has done fine with growing their subscriptions and thus increasing their resources w/out any gamification or gimmicks. The app has had a facelift, bug fixes, and some additional features added over the years, all of which have not changed the core focus of TR which is to make you faster. I don’t believe I have ever heard Nate or Chad say anything about entertaining or distracting you while you ride indoors.
Trying to be all things to all people is a sure way to failure. TR is not everyone’s cup of tea, just like Zwift is not for everyone. Furthermore, TR is not competing w/Zwift. While there is some overlap in the user base, TR and Zwift are not trying to grab the same people.