Well, there’s a few other issues present here.
Firstly - presently the marketplace already has a lot of issues with customers often buying things without reading ‘small print’ such as whether packs are supported on VR and mobile devices, resulting in unhappy customers that leave negative reviews because the marketplace doesn’t do the best job of presenting important information. As such, I can imagine a lot of creators not wanting to risk going down this road because if someone buys it unaware that they needed to own another package, that will result in all sorts of issues for the creator. The marketplace needs to be laid out in a more user-friendly fashion, or people need to be made more aware of the fact that they actually need to READ the ‘technical details’ section, rather than just looking at the screenshots and video. That said, creators also need to be made accountable as a lot of products don’t even list things like whether they are multiplayer-ready etc. When we submit products, epic have a set of guidelines, but the details in the technical details have, in my experience, been entirely up to me with what I do/don’t fill out and include… which is ludicrous. All blueprint assets, for example, should list the same details so that if someone is looking at two similar assets, they can make an informed decision =/ Add to this the fact that we have a very small space for the item description, and you end up with a scenario where a lot of customers don’t read the information that is important (because it isn’t front and center) and creators don’t list the stuff that may make their product less appealing than a competitors.
Secondly - I think you will find that a lot of the creators on the marketplace are specialists - they are either art guys, or technical guys, or sound guys, etc. In order to do what you are talking about, a lot of the time you need to be reasonably skilled in multiple disciplines to be able to make best use of it, other wise you jsut end up with a lot of pieces that the end user has to put together themselves, resulting in the product not actually saving that much time, thus lowering how valuable it is. In theory, this could be alleviated by creators working together - however, Epic do not allow for creators to share revenue, so you are left in a situation where one (or more) creators would be left relying on another creator to be honest about the sales of a product and share the profit fairly. That’s a pretty big ask for people who are relying on this income to live on.
And finally - as mentioned, Epic have not come down with a hard ‘yes this is allowed’ yet AFAIK. They have said that you are allowed to make packs that rely on the free plugins in some cases… but beyond that their response was (last I saw) “if you do this, we would need to assess this on a case-by-case basis”… Given the amount of work that marketplace content takes already (to ensure the quality, meet epics standards (a lot of which are very counter-intuitive) and so on), the prospect of spending hours upon hours on something to only possibly have Epic say “oh nah, we don’t allow that” is really waaaaay too big a risk for most creators to take.
At the end of the day, there are at least a small group of us who would LOVE to be able to make modular addons for our packs. I know I would be releasing heaps of smaller addons for my Multiplayer Survival Game Template if I could, and new features would get added to that pack a lot quicker as a result, because I would be able to invest more time into them knowing that I will reap some profit from them directly. As it is, I’m left making free updates, with no garuntee that it will increase sales at all, which means the updates are lower priority than a lot of other things. I know that Allar has expressed interest in doing something similar for Generic Shooter as well. I would also have made several packs with other creators by now if there was a better (see also: any) shared revenue system in place - but because there isn’t, and I don’t have anyway to actually ensure that everything is fair to myself and any other creators, the risk is just far too great, so I’ve turned down the propositions as they have come up.
As it stands, Epic’s system means that creators and customers alike lose out because they just don’t have the infrastructure, commitment or even communication to facilitate addons like this. It’s super frustrating, and as a creator who really REALLY tries to ensure that my product is top of the line, with constant updates, lightning-fast support, etc. it’s really disheartening.
Also - your site loaded, but only after about 10 minutes and it has heaps of missing images and such…