I'm sure you'll get your wish further down the line, but bear in mind that not every series has the same licensing rules regarding its participants. In fact, the same rules don't necessarily cover all participants! I suspect in this case, there are different rules regarding those with manufacturer/team entries to those privateer individuals also running. As for the extra skins, I think we just treat those as a bonus, which we didn't have to get but add a bit more value for (relatively) little work.
That I am quite aware of. There is a reason why Manor wasn't originally in F1 2015, and there is a reason why Kevin Magnussen isn't in it. And that's fair enough, slightly boring, but fair enough.
My hope however, is that we get an RX game (either standalone, or a part of something, like DiRT Rally) which includes all these kind of drivers, not only because it's slightly more realistic that way, but everyone should see the value of it. It is slightly easier to convince a sponsor to fork out that little bit extra, if you also can tell them that the car will be included in a game, that will reach millions (sales + youtube + social media +++) through a game as well as TV-coverage etc. The goal should be to get everything like that in a game, or at least, that's my hope. I don't expect it. I just got a glimmer of hope when I saw Veiby included (and then a slight disappointment when Rustad wasn't included). I've always, since I was 7yo dreamt of a proper RX game, I'm now 24, and it might happen. Though, the point-system needs to changed!