I'm trying to pick up what you're putting down, and I like the overall concept behind your assertion, but i voted "no".... Let me explain why....
1-The pig-bike movement of the 50s that led to the musclebike era was, imo, a fashion trend that resulted from a new generation of young ppl who were reacting to the lack of innovation brought to kids' bikes in a brief period of bike-industry stagnation. Like many modern rat-rodders, these kids' creations were driven primarily by aesthetic considerations but those kids were trying to move forward; to make progress. The prevalent trends in rat-rodding seem to be towards holding onto old stuff and/or trying to make new stuff look old (eg, look at all the threads lately about faux patina.) Essentially, the pig kids were shaping the future, vis-a-vis musclebikes to come, whereas the majority of rat-rodders are working from nostalgic impulses, at least in part.
2-The Marin guys, for the record, preferred the extra clearance provided by the balloon frames over the middlweights. More to the point: the Marin guys were performance junkies. Many of them were competitive road racers, and virtually all of them were building those old balloon frames for a very specific purpose: to be as fast as a bike could possibly be, offroad. Some of the guys built for the downhill races (like Repack), whereas other guys (eg, Steve Potts) were building old cruisers to be as competent as possible for XC-style riding. The majority of the klunker guys couldn't care less about aesthetics; they wanted performance, and durability b/c durability impacted performance. Based on what I've seen on this forum and similar forums, plus the ratters I've known personally, there is absolutely no interest in performance for many ratroddin' cyclists.
Another thing that sets the klunker folks apart from folks like us is that, their bikes were "cutting edge". If Alan Bonds built you a bike in the 70s, relatively speaking within that time period, you were running the absolutely latest and greatest in offroad machinery, even if many of the parts were vintage (even by 70s standards). Many of those guys went on to design/fabricate their own brand-new scratch-built frames, or even their own bike companies. While we RRB types share a common link insofar as we repurpose old stuff and we try kludging/fabbing things that shouldn't work until they do (just like they did), we're doing it b/c we think it's cool....they did it b/c they had to. If something like a Spesh Demo 8 had existed in the 70s, that's what they'd have been riding Repack on, rather than on Excelsior- badged Schwinns.
We are at the point now where we can buy incredibly specialized (with a little "s"; not the bike brand) bikes for just about any niche in cycling. If we want a hardcore mtb, we can buy one. If we have a mild mtb, we can buy bolt-on aftermarket bits to improve it. Similarly, we can buy ready-made cruiser/"kustom" style bikes at the LBS or the WallyWorld, too.... and I suspect that many of us build b/c the pre-made cruisers don't look or feel as "cool" to us as the ones we can build. But, those are mostly aesthetic concerns, aren't they? (To be fair, I built my daily rider as a commuter cruiser, with good brakes, dynamo lights, stuff like that.... which is hard to come by with most current-production cruisers. And that was more about function than form, but I'm pretty much in the minority here, and besides, if all I cARED about was function, I'd have bought a purpose-built commuter bike, right? So I'm still more of an aesthete than a pragmatist....)
As for creativity/innovation: I see tons of creativity on here, and among other folks who prolly fit under the "ratrod" tent. I also see a lot of imitation, tired reworked concepts, half-hearted "mods" that involve little more than flipping the bars or a tire swap, etc. So, while there are a lot of very creative folks rat-rodding, there are also others entirely bereft of creativity. Most of us prolly fit somewhere in between. Innovation? I'm not sure how we'd measure that. We're building almost entirely to subjective parameters here--- aside from trying to keep the cost low, almost none of our goals can be measured in objective terms. The guy whose bike got to the bottom of Repack fastest, he knew he had the best bike.... or, at least, he had a danged good bike and he was a great rider. I guess we can count the "likes" on our thread, or the votes in the build-off, but that just measures the rate of recurrence for positive opinions. It's still subjective data about the aesthetics of the bike in question. Innovators in the road and mountain world can measure their success in the weight of the bike, the drag coefficient, the victories at races....and sales figures. These are objective, quantitative parameters. We can do no such thing. Even if we did decide to weigh our rats, or measure how aerodynamic they were, it'd be a bad joke as far as "innovation" goes, b/c the rest of the bike world is eons ahead of us as far as those things go.
I guess most of the above seems pretty negative, but I don't actually feel sour about any of it. We're into this for the fun-factor, as I see it. I can only speak for myself, but I do what I do with bikes to have fun. And, if you're finding new ways to enjoy yourself and your bikes, that's innovative and creative enough for me. If you look at a bike as an artform, it's easy to see how ppl like The Ren Man, Fordsnake, Kingfish, etc could be considered geniuses... but it's unlikely that they'll actually inspire alot of imitation among current bike manufacturers. Those guys are happy to sell a black bike with red rims and whitewalls, and call it a day.
And, of course, I'm not above any of my own criticism; much of it applies to me as well. I steal ideas, rehash tired concepts again and again, and I ride trails on inefficient bikes. (I'm old and fat; why shouldn't my bike be old and heavy, too?) I got into it mostly out of frustration with the planned-obsolescence that pervades modern bikes; I can have as much fun on my trails on a singlespeed cruiser as I would on a new bike, just at a slower speed. But, I do try to build things that look cool, and I absolutely fall prey to sentimental feelings and nostalgic builds. Like I said before, I do it b/c it's fun. I don't do any of it b/c I'm an innovative genius, or even b/c I wish I were an innovative genius. I'm just trying to have a good time....