I’m sure they would. However, without having THAT aircraft, and ideally THAT livery, installed on every simmer’s machine, it is currently not feasible. An alternative method would be for MS/Asobo to maintain 3D models of every single available add-on aircraft for the sim, then download them in real-time to every simmer who spawns into the visible area around another pilot. That would be a very difficult challenge. Not all aircraft devs produce well-optimized models amenable to easy download, and even for those that do, 3D models in the sim have what are called LODs, Levels of Detail. That means, the closer you are to another aircraft or object, the higher detail it will have, the further away the lower the detail. There are sim guidelines for developers about this, but not all devs adhere to them, and determining which LOD to display at a given distance, and therefore which version of the model to stream out to everyone observing that aircraft, gets messy. Plus having models of every possible aircraft in your rang of view in a busy multiplayer session will heavily impact system memory and (more importantly) GPU VRAM usage.
Model-matching utilities exist, and they work reasonably well for airliners at least, but they can easily take up many gigabytes of additional storage for all the 3D models. I think FSLTL’s library is close to 30GBs; JustFlight’s FS Traffic is like 15GB or something. I believe AIG’s is even larger but I have never used it so don’t know for sure.
So for now, that’s why unless everyone has the same aircraft installed that you’re flying, they will otherwise just see a generic base-sim model.