Backwards compatability is the biggest road block to enhancements in performance, new features and new capabilities.
I fully understand where you are coming from, but as we saw when FSX was released - a great many "FS2004" aircraft were using FS2000 gauge technology. We are going to lose some addons with every new version. And we have to remember and budget for that to happen.
Of course, nothing keeps anyone from staying with a older version. FS2004 has a strong dedicate following.
@ PawPaw's house - near KADS, Addison, Texas, USA