||Yes, Paradox supposedly incorporates some real locations but the focus is the unreal one + the cube that comes out of nowhere in the end.
In RLU there's only a real location and The Lab cube's origin is clear and simple. We see how it's excracted.
Back to Occam's razor, The Lab works just fine without making it an artificial machine-induced dream. It's simply unnecessary.
And speaking of Rose, if she'd built such a machine we'd probably get a hint avout it in her digital journal. Instead we see her still thinking of Laura and producing cubes. A Paradox dream machine siply sevres her no good for her goals.
On another note, I'm afraid, you are mistaken about "the simplicity" theme. Because you seemingly misunderstand what's really happenning in each case you've evoked.
What the Eilanders did wasn't about Jakob's ascension. It was a different ritual with different purposes and Jokob was supposed to stay dead. It was Coraline who invented the elixir and outsmarted everyone by saving Jakob's soul at the last moment. Her way was still a bit exotic but it's not because she couldn't do like Aldous. The brothers were likely using her lost knowledge after all. It was just her plan that required such a complexity.
William and Albert also had different goals: one wanted to simply live, the other wanted to preserve his body and personality. And I wouldn't say Albert's got it easier. Creating cubical devices and convincing one's past-selves to cooperate isn't exactly simple.
And finally Owl could create the golden cube right from Laura's birth. All he needed were William's elixir memories inside Laura's cubes. No preparations, no nothing. The thing is, the golden cube isn't his endgoal, it's a mean to create his successor. That's why he was preparing Dale and Laura.
And again, saying that Albert has got his cube easier is underappreciating the effort he and Rose put into their very complex plan.||