Honest question. Who is actually asking for folding phones?
On a theoretical, pie-in-the-sky science-fiction level? Me!
I have an iPhone 11 and an iPad mini. Sometimes, I take the mini with me on a commute, because it's nice to have a bigger screen. But it of course takes a much bigger pocket, too. What if I could unfold the iPhone 11 into an iPad mini? Best of both worlds. Cool.
In reality, this isn't a thing. Foldable phones are bad when folded (the ones that work folded at all, anyway), and mediocre when unfolded. They're the worst of both worlds. That seems to be true for every single product in that area so far.
It's possible foldable phones are where smartphones ("PDAs", then) were in the early 1990s: a decade and a half away from being good. It's also possible that this is a pipe dream that, once you think a little about physics, doesn't make much sense.