I love the Duo 2, but if MS won't provide a sequel, I'm not sure I'd go with a Google Pixel (as the next closest hardware option) over a non-folding Galaxy for the better Windows integration. I also strongly dislike the external screen for all the added wasted thickness (one of many problems with a single foldable screen over 2 screens). If the Pixel fold is anywhere near as thick as the monstrous Galaxy Fold, that's a dealbreaker for me. On the other hand, if Google has managed to make something as thin as the Duo 2, that would nullify that concern.
I love the 3:2 aspect ratio of the Duo screens. If the Pixel Fold's screens are close to that, where Samsung's are quite narrow, that would be a compelling advantage to the Pixel over Samsung.
I also use the Duo's tent-mode posture all the time, either to set it on a table or wrap around my hand like a self-contained pop-socket for stability. So far, none of the foldable devices support this. I know Zac has pointed out that a foldable screen is too soft and easily scratched to be on the outside, but I think I'd rather take that risk than settle for a screen that can't fold open. I wish someone (ideally MS) would offer a foldable screen where the screen is on the outside instead of the inside, eliminating that absurd hack of a solution of a separate external display and its extra thickness.
I'll read the reviews and accept that at some point I may need to move to a non-Duo phone, but for now, I have no need to update my Duo 2, which is almost the perfect device for me. MS has some time to update before I'm forced to an alternative. While I don't dispute that annual updates are probably important to the marketplace as a whole, as long as the phone works and is fast enough to run everything well and is not missing any critical features other phones have added, I'm happy. The main thing missing from the Duo 2 for me is Qi charging. Other than that, I'd like an ever better camera, but Duo 2 hits the mark for being "good enough" in that regard (where the Duo 1 had an even better, thinner form, but fell FAR short with its terrible camera).