If I have well understood the Life project from Jeff the path of vehicles movement can only be created manually under 3DS Max for now. It is the manual side that bothers me (in addition to the license of the proprietary 3D software). In the long run, could these paths be created automatically, for example from the OSM route network?
There are two things going on here, one is the routes for vehicles to follow, and the other is whether to render roads on top of ortho photo roads.
Aerofly should definitely implement vehicle routes from OSM data. Given how well the animations work in Jeff's demo, with minimal performance impact, it's probably not a huge leap to read these animation paths from elsewhere. Seems like a relatively easy win to me.
As for whether to render roads on top of orthophoto roads, I've never thought that roads in X-Plane look particularly realistic. Being vector, they're well detailed if you get close, but they generally stand out like a 'sore thumb' against the ortho backdrop. The asphalt, concrete and tarmac used on roads come in so many different shades that it never matches well.
I noticed that the on the MSFS 2020 trailer video the roads show vehicles moving on top of high-res orthophotos. They haven't tried to render the roads as geometry.