Jon Burton, who founded Traveller’s Tales, and has worked on many LEGO games, made the claim in his Coding Secrets YouTube channel. It’s a six-minute long video that goes into some technical detail. But the basic takeaway is that because the alternate dimension bits are so small, and reuse assets, they don’t need a fast loading SSD. And for the most part, he is probably right, in the sense that world switching is only really a thing in one level. The rest are restricted to smaller pocket dimensions less than 10% of any given level. And in the opening sequence where there is a lot of dimension jumping, the whole thing is a railroaded sequence where pre-rendering is possible. Though crucially, the video leaves out the one level where I said world switching is a thing: Blizar Prime. There, it does seem as though the speedy SSD is definitely needed for swapping assets in the map in a second. Because it’s not a railroaded sequence, it’s unlikely that a console can predict, and therefore pre-render, two whole levels and switching between them. At least not without requiring too much RAM to be practical. (Source: Coding Secrets / YouTube via VGC)
