In my opinion, talking about the linux side that I live, P3D got without doubt to follow the repository way of distribution because is the way to go on the main desktop distros and because the user is accustomed to install packages in that way, therefore P3D got to push to enter into the main deb and rpm repositories one day or another (pro_rsoft is already heading in that direction I guess). So, as long as P3d library is in that stream, the game dev gotta just think to make his game and build his package with the tools provided by his distro defining P3d just as a dependency, as well as eventual several others used into his game, like pygame and so on.
Can’t see a similar workflow for Windows and Mac though…