Strava would kill Zwift, Rouvy and Fulgaz, if they only tried
I think Strava is missing a HUGE opportunity not competing with the other indoor training apps. All the data is already here on Strava. Millions of segments with hundreds of riders on each with elevation profile, time, power, heart rate. All they would need is maybe few basic road design in 3D just like Zwift and the elevation would be generated based on the profile from actual segment on Strava turning the flat road into a hill. Vary easy to do using DirectX or OpenGL engine and profile generated from map terrain data or GPS track.
Now I would just go to Segment Explore, scroll around the map to find segment I like and hit generate. Pick past riders from the list to compete with and go for it. The computer would place virtual riders next to me based on their recorded data and we can race to the top. Now I can see how I stack up against other guys or KOM winners or even ride against my own rides I did in the past. I bet this would be the best indoor app on the planet. Charge it $20 per month, use the $$$ to actually drive out there and film the segments in 4K (start with 100 most popular in each state) and project the Strava riders on it just like Rouvy does. Now I'm riding realistic looking segment filmed in 4K with riders that actually rode it.
One can only dream of such an app.