For me, as a longtime occasional cyclist (get into it for a few years, stop, restart, etc), once upon a time (1 year) competitive college athlete, but mostly lazy slob.. it involved my wife buying the Peloton bike .... then 6 or 8 months later when I was regularly biking to work, but still gaining weight... started seeing a personal trainer.. he encouraged me to track what I eat, and I've now been using myfitnesspal for 3 years. You could point to any one of these things as being what did it for me; obviously the structure and advice from seeing a trainer was crucial, but #1 on that list for me was MFP, so yes, an app (and a free one at that!) The feedback loop of what I inputted there showing up on the scale the next week was addictive. It was the first time anything really "worked" for me. #2 on that list is the Peloton, in particular once I started doing Power Zone training, where I could join a team, stick to a schedule, and quantify performance gains that I can now see when I set personal records up local climbs on my road bike. I'm also in a running club and compete on the road and cross-country.
Again, everyone's path is different, and I absolutely could have done any of this on my own, but I'm 39 years old, and the reality is, I didn't until I started using an iPhone app. And the data and quantifiable results of my various forms of training are what keeps me going, and reinforces those habits.
That's not my argument at all. In fact I'm reducing the entry cost to achieving a fit lifestyle and explaining what's actually important.
You don't need any apps, you don't need to pay a monthly subscription for a digital service. Maybe you might have to pay a membership fee at a gym or a boxing club or some place you can go to do to the thing you want to do. The local canoe club, who knows.
I'm proposing these apps are like fad diets, people will pay for them, see they don't work, and move on to the next thing, perpetuating failure and bad outcomes. I predict this $500m investment will blow up as a failure, that was more the point I was trying to make.
People just need to fix their behavior. They need to find an activity they like, prioritize it, create a routine, and make it part of their life. People have been doing this since before apps existed, and it's all it takes, and apps can't do that. You have to do it for yourself.