This is something I've been trying to tell people for a long time now. One of the major things we did last year was send out hundreds of emails to asset developers and similar asking for 3d asset donations to the project. Epic itself provides an avalanche of high quality free assets now, through partnerships with industrial scanning organizations.
On top of the donations, and the free assets we pick up from places like megascans, we've been serially purchasing any relevant assets we could afford for the entire time, and I've been converting and filing all the 3d assets I bought for work over the last decade so they are native to UE5.
This was one of the primary reasons I structured things the way I did, with a corporate entity with unlimited intern slots. When a studio buys a set, say an old west town, any filmmaker working for that studio can use that set. You don't have to rebuild the set for every film. One of the things Save Point does is buy and organize assets en masse, and then anyone working in employ of the studio (the internship is so I don't have to turn 99% of the people away) can freely use those assets legally, since they are licensed to the studio, and employees are under the umbrella of that license. It's limited in use to an educational scenario, but that's a big deal, because having nearly unlimited resources can really accelerate the learning process.
TLDR/ I've gathered up tens of thousands of dollars of these assets, and made it so beginning directors with more talent than money can work with them for free. The catch is that everyone has to contribute to the main project, but that contribution only needs to be a fraction of a single cell, and a creator can have partial ownership of cells they help produce. I can't legally buy assets and give them to people, but I can let them use SP assets to work on SP videos, and then share revenue from those videos, just like WB or Sony does with it's props. At a minimum this system lets people test drive thousands of assets at no charge, if they're willing to test in the form of cell projects. Many publish to the Dust channel to get their short films seen by a larger audience, the only difference here is that the Dust channel doesn't provide your entire filmmaking kit for free.
Right now we have about 1600 of these UE5 asset packs I think, ranging in size and cost from 10 bucks to 500 in some extreme cases. A pack would be something like you showed above, with dozens of models, sometimes hundreds per pack. All told we have tens of thousands of models and assets.
I'll show you an example. I buy stuff on sale, always, and just check prices every week. This pack was 50% off one month and cost me $12.50.
Engine hall filled with sparks, steam and animated old-style machines.
www.unrealengine.com
Here is one of the many segments I made with it. Though the pack is just a single hallway, one can of course extrapolate it into something more grandiose.
About the water sim above, I think that's the same one I already bought and have been using for the flood project. There are about 3 good ones, and about 10 lesser ones. This one was actually one of the most expensive assets we ever bought, on sale for 200 I think, it's called Fluid Flux.
In short, when people join, we give them access to nearly unlimited assets, and they can learn with them, experiment, etc, but are legally limited to publishing final works based on those assets to the corporation's channel where they are licensed. It can still be "Directed By User X", it just has to be on a channel owned by the asset license holder.
Here's a snapshot of the Save Point 3d asset master directory properties. 107k folders, it's becoming really difficult to remember where everything is. This is a 16 tb drive, with about 90% currently used by just existing assets.