(From random thoughts)
As someone who sometimes has similar feelings - virtually identical ones about MFB, in fact, I understand your position, Zero-G's gimmick interested a lot of people, but the other "gimmick", the "buy two beyblades to make one useable one" is really a terrible tactic for keeping people in your position interested. It's one of the reasons I felt closing off the MFB metagame after flash may be a good idea - that way, the metagame is stable, at what was a fairly well-balanced point, and people can buy that stuff and play it on a level footing. But, in the end I personally felt the other way was a good idea, as long as a close eye is kept on Zero-G's parts and game balance, for numerous reasons. That said, I think the rate the metagame "burns through" parts is really extreme, and I know for sure you're not alone in that - in fact, it's one of the most common reasons I hear for lost interest.
It is a real shame to see people like you, and everyone you listed, losing interest - though I only kept mine thanks to plastics remembrance day in the end. You guys were some of the largest influences for me starting out - though I am and always have been far from "perfect", you all gave me something to aim for. (Something which I personally feel I've hilariously failed to live up to with certain activity, much to the displeasure of a few people, I'm sure.)
Perhaps one of my biggest complaints back before a whole swathe of you slowly disappeared, or at the start of that disappearance, was the inactivity of the advanced forum. Now I'm there myself, I can see what those of you I criticised for not pushing hard enough were dealing with, and my accusations of inactivity and irresponsibility seem rather rude (in most cases, anyway), given the perspective I now have, and now that I see just how hard it is, even in that position, to make stuff happen and get things done, especially with the small size of that forum in terms of active members.
The other issue these departures have caused is role models - and a particular lack of "good" role models. There are obviously still a few very, very good examples of what people should strive to be around the forum, but the number is much, much smaller than when I started out, and I do sometimes wonder if this is in large part, at least, the reason for some of the issues I feel are most problematic for this forum nowadays.
From my perspective, again, and sorry if I'm being self-centred, the disappearance of a lot of people has been "a bit of a pain" for my plastics interest. It leaves me a very small set of people to actively talk to and learn from, other than the few conversations I've had with members of "older vintage" - which are always some of the most interesting and insightful conversations I have. Getting answers for certain questions about HMS is a darned pain too. Of course, this isn't limited to my plastics/HMS interest - writing beywiki articles for earlier releases is rather hard without the perspective of those early testers/people who were around there and saw how they affected the metagame.
I don't really know where I'm going with this, but yeah, basically I know that feeling too. It's good to hear from you again.