So I want to preface this question with the note that I am not trying to criticize the following people, but I just don't really get it.
Are people with severe bushing madness REALLY inhibited by not having these wacky combos of obscure setups? I totally get wanting replacement soft/hard bushings depending on basic weight and turning preferences. I'm not sure I've ever had deck or truck madness, but those make a lot of sense to me. Bushing madness doesn't. I can't imagine a scenario where I was like "Yah I woulda landed this if I had a Riptide 94 lower rear with an Ace low hard top and my front with a Thunder conical shaved down 2mm lower and an Indy aftermarket black top with Krux pivot cups.
I think a lot of it stems from the frustration of not being able to get their trucks to what they want easily with just basic single brand parts, so the evolution of trying this and that and then keeping with whatever they currently have with the products available at the time.
That very specific modification of their gear, compared to buying a set of trucks, skating them as is giving the bushings time to break in nicely, or just as some people I know say, "New trucks suck, so the first few sessions suck, then they get used to however they feel" or something similar, from a guy who rips harder than anyone else I know, so I take that as an example only, but I also see a few things I think he could have fixed to make his board skate better, as much as he doesn't want to hear it.
For others, maybe the changing to inverted kingpins or other mods, then leads to increasing bushing mod or change ups, so one other person I know, no bottom washers, cut down bushings, trimmed to whatever height according to whatever bushings he can get his hands on, the softer the better, truck down to axle, kingpin down so low he has to cut bushings otherwise they just don't fit, etc. It works for him, so I guess just replacing hangers when he needs is easier than trying to get used to a brand new set of trucks.
I have boxes of the old Indy low head bushings, which work nicely, started on new trucks, kingpin nuts fairly flush, then tighten down as bushings break in, so then I have the kingpin nuts a few threads down, which I then angle grind off to never have clearance issues and the bushings last the life of the truck, so that is my simple enough fix, even though some people have said that is a lot of work to get things going.
Guessing that is not quite what you are asking about, but when people do tinker a lot with a few things, more so than having a whole skate shop of bushings to try, I think they are more likely to be trying this and that, just to get their own board working just how they like it, more than finding the exact right bushings from twenty to fifty plus options on the market, which is both costly and unnecessary for the most part.