Yes, thats indeed a good question and to be honest, I can't really answer that question, I can only tell you what I think.
I think that Epic was kinda disappointed with the results of the UTPG team and 4.51 was no "entire success". Why they didn't release 4.68 is still a bit unclear to me, as it would have fixed some things already. From what I know they wanted to finish the Mac port first, or something in there wasn't ready yet. Then the team became more and more inactive. I have the 4.68 sources also.
I was grouped into UTPG but was never really part of this team. When I joined UTPG formally they were pretty inactive already, but I was never really part seen technically, as I concentrated at this time only on Unreal 227.
The next "unsuccessfully project" in their eyes was probably 227 itself, although I continuously worked on it, the progress was slow. Shambler was at this time with me, but soon moved on to 2k4. Jeff Morris was the responsible person at Epic when I started and he always tried to help and was always there for questions, but he left a few years ago and nowadays now all this NDA stuff seems to be only a pain in the ass for them.
When I released 227f, Epic was already very uninterested whats going on, and nowadays I only get the answer for anything I write to them: "we don't have the bandwidth to", such as the question for making a new UT patch based on the 227g code with "We don't have the bandwidth to oversee such a project", the answer for releasing my Mac OSX port was exactly the same. You can imagine how disappointing it is- I have a fully working OS X port (well except OpenAL at the moment) and can't release it.
Basically I have anything needed to make a new UT patch, but I'm not allowed to.
At the moment it seems I can be happy that they don't deny me 227g.
All hope is that they will show some interest again in the old games if 227g becomes a success.
Well next time Epic uses the excuse "we don't have the bandwidth to" you tell them you do, then you get with me and I'll make it happen.