Well, 7bit is a little different, isn't he
Let's take another interesting example: GMK Dolch. Dolch is a colourway, like a color scheme, but with a bit more organisation. Ivan's GMK Dolch is a recognisable "design", though, since it has certain features that set it apart from every other Dolch set like DSA Dolch (such as the colour pack and choice of legends or text on the mods, not to mention the profile and font differences), despite the fact that it has no actual custom legends. I'm not comparing Ivan to Michelangelo, though.
On the other hand, his current IC for Jelly POM sets is really just an IC for something the manufacturer will provide, most likely without even a particular colour choice, just blank white POM caps. There's really no design there at all and he's just providing the service of organising the GB so we can get them at a good price.
7bit's Round 5 is somewhere in between.
However.... Even Round 5 is a "limited" run, as are all of 7bit's GBs. I can't order Round 4 Sphericals any more, can I? From the Round 5 page on DT wiki: "Whenever SP starts production (early March), there will be a limited number of kits available, until they are sold out! "
In one sense, all GB sets are limited editions as they always get made in batches. A set can be run a number of times, but of course the demand will reduce with every run since most will have got in on the first run (unless it was poorly marketed, but proved VERY popular).
My personal experience about sets I participated in the IC's on and had a second run lead me to the conclusion that I prefer sets to have just one run. Ivan's black on black started off as an IC for blank black PBT which is when I joined in. Dyesub options were added. Then there was some back and forth choosing the colours to use so the dyesub legends would be visible, but the base plastic still dark enough to be called black. When it looked like we might not meet MOQ, I ponied up and ordered 4 sets. Then there were problems with the first batches of plastic, then problems with the production schedule, but eventually we got our caps made and delivered. Yay!
Then Ivan did a second run of them. I felt a bit cheated, to be honest. I invested time, stress, suggestions, feedback, ordered more than I needed to help get them done, waited a year to receive them and then... you could order exactly the same thing at a cheaper price for round 2 and get it sooner. Not only did the financial value of the sets I bought drop way below what I paid, but the emotional and sentimental value attached lessened considerably. Doesn't change the fact that they're great caps and I'm happy more people have the opportunity to buy them, but it still felt.... wrong, somehow. And I doubt there's going to be enough interest for a 3rd run to meet MOQ. Demand for that set is not high any more, as supply has outstripped it.
Somehow I'm okay with Jukebox for now. Probably because the overproduction that's now available on PMK is part of the same initial run? More likely that I feel it didn't get as many orders as it deserved, so the new sets are going to "late original buyers" or something like that.
You can't begrudge someone feeling a set is more valuable if they have invested in it emotionally. I have yet to sell any of my sets, though, only traded ones that had less total perceived value to me for ones with more. This is a personal thing and both parties feel they're doing the same thing, trading something they want less for something they want more. The value of a set is not just financial.
Having just one run and making sure people know it will only be a single run does a few things:
1. Increases demand which helps meet MOQ's since people know they won't have another opportunity to get the set.
2. Ensures that the majority who want the set get it due to the way GB's work.
3. Helps maintain the perceived value of the sets that are produced, which is important to some who participated and is a bit like "giving back" to them by the designer, thanking them for their support of his design.
Please note I'm not talking about the financial value here, just personal "perceived value". IMO, having limited edition sets creates real personal value for the buyers, not just the "collectors", but all buyers. It's nice to be typing on a "limited edition" set, it's just that little bit more special somehow. In the case if keycap sets, it's not really "exclusivity" (since anyone could have ordered their own set at GB time), but rather a marker of a particular moment in a community. If you missed that moment, it's okay to feel a bit left out, but don't worry. New set designs are coming along all the time and it won't take long to find a set that really "resonates" with you.
TLDR: Community designed keycap sets are special. Single run sets retain that "specialness" more than "mass market" or rerun ones and mark a particular time in the community. This is not traditional "exclusivity", but rather time-based "inclusivity" if that makes sense. Community designed sets are not, and should not be mass-produced and mass-market products, IMO.