Agreed it must be a fine balancing act between development needs and the money available, the more so during this so called recession. Nevertheless, any franchise must evolve and while Trainz, RS or any other sim may not be GTA you can't keep selling it on a 9 year old core. (I doubt GTA IV would have sold so well had it used the original top down view

).
Within that budget there ought to be money for R&D into some of the more basic issues - better AI/autonomous dispatcher/timetables, control over curve radii, tunnels at any angle, seasonal variations within the same route. Everyone knows or has their own personal wishlist!
The community has been supporting Auran financially even if it has involved some leaps of faith that ultimately disappointed - I purchased TS2009 but in all truth have barely fired it up. I just renewed my FCT even though, at present, I'm focusing on trying to develop another RS route. I don't think there should be any illusion that if money wasn't coming in to Auran from Trainz, it would have gone the same way as Fury and that there are still unanswered questions as to why the sudden switch from the avowed policy of releasing TC culmulative packs as the way forward to TS2009/X (unfortunately in the process leaving TC3 - probably the best version to date - out in the cold).
In all likelihood I will buy TS-x even if only to satisfy my curiosity and that I live in hope of one day getting the perfect train sim but Auran do need to take on board there will come a point at which even the hardened fan will say enough. I think quite a few of us will be watching Rail-Works to see if that follows a similar path and you already have the added complication, from the route builder's POV, that in order to get enough 3D models to create a decent freeware project we are having to buy payware routes (Foliage Packs, IOW, Rascal etc.) which end users of your projects are also going to have to buy.
Still what we have is far better than what preceded - the text based output of the likes of Simudrive. We can only hope that all the companies currently supporting the genre see enough of a future to keep going and hopefully updating too.