Yeah most of it stems from the asset marketplace. If you look at Unreal's marketplace or Unity's asset store and sort by top seller (and especially the free cat

Yeah most of it stems from the asset marketplace. If you look at Unreal's marketplace or Unity's asset store and sort by top seller (and especially the free categories), you'll probably find exactly the things that you're talking about. From particles to sounds. Great resource, but a lot of developers don't really customize them much and they tend to be the things people are noticing per engine. You are on the money regarding self-selection as well. A small team is probably going to pick Unity due to all the preconceived notions, and alongside this will probably create similar looking visuals to other Unity games due to a reliance on the asset store if their team isn't heavy on visuals. It might seem like I'm focusing too much on the asset store, but it goes for custom assets too where even if you're working smartly, you have to blend those premade assets with custom ones. If you're on a large team working on an Unreal game, it's probably going to be realistic looking for example so you're limited based on what lighting makes the skin look good, what particles make sense in a grounded world, and so on. It's technically possible, you're only going to run into problems when you then try sharing assets from different stores (audio and textures excluded), where you now have to recreate it from the ground up to match in that other engine. So you're also right about that aspect! As real examples of the flexibility of modern game engines, Octopath Traveller Yoshi's World, and Arkham Knight were made on UE4. For Unity; Cuphead and Escape from Tarkov.