I do not want to start a Jihad here. As far as I am concerned I enjoyed all of the RM editions. While I think I have most of my time playing n RMSS, I think I have the books from every version.
I would agree. We didn't use RM1/RM2 as full on system (unless you want to count early MERP) but we did use it to revamp D&D with. I've got everything from the first Arms Law through the most recent RMFRP stuff that wasn't just a republication of RMSS materials. We use it all (obviously converting things over).
D&D 3rd Ed - When people were leaving Role Playing WotC decided to reboot the system. They developed 3.0 and used elements from many different systems. At the rollout convention here in Denver I looked at the head of the development team (Johnathan Tweet) when he could not explain why something was done and asked "What the source document?" (I handed him my hard backed copy of RMFRP). I thought he was going to blow a gasket. Truth hurts I guess. [For some reason I think Mr. Tweet thought I was a jerk...go figure :-)]
We were very familiar with both systems at the same time in the mid to late 90's (D&D and RM) and I would say the influence of RM on D&D started before 3.0. Each revamp of D&D became a bit more like RM and while it's reasonable and totally justifiable to say all systems have an influence on each other
and that similar ideas can develop independent of each other I don't think it can be completely dismissed. Take for example the fact that someone like Monty Cook came from RM and moved to D&D. You just can't ignore that influence. Note, I'm not saying there is anything
wrong with that... but I wouldn't be shocked by the reaction you seem to feel you received.
Now, further editions were often seen as a money grab by Hasbro as the most amount of money is made on new versions of an RPG and the versions came out a bit too quickly. But I suspect a big motivator was probably trying to appeal to MMORPG players. Which I can understand, but I'm not sure that's really all that possible as a short term goal. I honestly don't think Hasbro really understood the RPG market when they first took over WotC. I think 5.0 is kind of correcting the ships course.
Regarding multiple editions. That's hard. I think existing RM users would be happier as a whole if you did that, that being dual stat'ed books and basically left RM2/C and RMSS/FRP in place. But that's assuming existing RM customers are still the future of the system and I really don't think they are. It also has the problem of there already being so much material out what could you create that's truly new? I think it would just lead to sub-par RM2 support and a short lived RMSS support. RM needs a new influx of customers. The two biggest problems are RMs past reputation and trying to find a way to appeal to the modern gamer. Will it still be a veterans game? Should it try to simplify or stay detailed? I don't think RMU committed to just one of those. Intentional or not I think it has a foot on each path when it needs to choose one. The biggest opportunity for RM to pull players in was during the D&D 3.5 and 4.0 window. That was probably a comparable opportunity to the decline of TSR window.
Then there's the problem that ICE is, essentially, a decentralized company that is everyone's part time second job. I don't fault anyone for that (well, I could point to previous incarnations of ICE, but we won't go there). It's just the current reality. That actually makes me ponder if the current goal of the ownership is to become a serious contender again or just keep the flame alive. Both have their valid reasons.