I don't know DAZ but...
Scene load time is an issue, Ocean talked about it in the latest
Dev Log.
But what Ocean mostly complains about is VRAM constraints, which is a hardware constraint mostly rather than a DAZ limitation. The more stuff you have in a scene (model complexity, number of models, number of lights etc.) the more VRAM you need to be able to load it in DAZ. It just fails to load if it runs out of VRAM.
That's why he talks about getting A6000 cards, more VRAM. The problem is A6000s render a lot slower than 4090s etc. Which is why no other AVN dev I know of are using A6000 cards, they're using 4090s etc. because they render faster.
When people talk about Ocean doing better optimisation, what they mean is reducing the complexity of the scenes so they're easier to load & render faster. But that requires compromises, reduce the complexity of environments, reduce the number of characters, use background chars instead of full models etc.
Ocean isn't a fan of making those sort of compromises. That's why he's reworking scenes he felt were too empty originally for example. And spending a bomb on A6000 cards for the VRAM despite them rendering slower.
Not at all, we're gentlemen after all. Scouts Honour!