Yeah, it is important to understand that the big rush in the beginning is:
1) Get root
2) Wait for Source code
3) Fix **** ups from the manufacturer
4) Make modifications [possibly from other devices] to improve Android overall.
It's been over a year, all that's been done. While improvements are still coming constantly...the bulk of that work for the Evo is, well, done.
I have to agree here. I think a lot of people have gotten into the habit of changing ROMs on a way too frequent basis, to the point where they're switching weekly with 4-6 Nandroid backups of different ROMs so they can jump around as much as they want.
That list above is the true goal of Android development. If I find a good ROM, and there's relatively little bugs (especially less than stock), looks great, gives me something flashy (like Sense 3.0) I can be satisfied for months at a time, not even updating most of that time.
Unless there is something that has yet to be perfected on the EVO, development could halt right now and it wouldn't hurt what we already have. Look at all the things that's been done for the EVO since release:
Wireless N
HDMI-to-TV mirroring
Hacked hotspot
Notification bar power controls
4G on CM7
Hacked Hulu (which is now pointless, but eh)
...and more I just can't remember right now because I haven't had my morning coffee yet. The EVO has actually evolved (no pun intended) over the last year and 2 months, and like any piece of hardware, we're going to reach the limits. But the EVO has shaped the future of Android forever, and that's what we need to remember most.
Our community has created some of the most amazing pieces of code Android has ever seen, and that will only get better with the 3D. Time to move on...if I had the money, I'd get the 3D too, but that's just because I can't root my replacement EVO...