If you look at Google's Android phone market share (currently 1.1% according to https://www.appbrain.com/stats/top-manufacturers https://www.appbrain.com/stats/

If you look at Google's Android phone market share (currently 1.1% according to https://www.appbrain.com/stats/top-manufacturers https://www.appbrain.com/stats/top-manufacturers), and consider that the foldable version is probably the least popular model in this not-really-popular phone family, it becomes understandable that they're not investing heavily into R&D for it...