I think there are a lot of people who would love to have a smaller form-factor for when the phone is in their pocket, with a large screen for when it's being used. The current state-of-the-art might not be very good for foldable phones, but the demand is there, and that's what drives innovation.
Foldables are a growing market in Asia, where they are more widely available. They are quickly becoming a new status symbol, displacing Apple. Especially in China where the local phone manufacturers are now completely independent and free to experiment.
Apple somehow completely missed the plot (yet again) despite being having the largest tablet marketshare. Google, to their credit, is now pushing developers towards supporting dynamic screen dimensions.