I think what these people are looking for, really, is an alternative to the Android/iOS duopoly that provides more control and less tracking, not necessarily Linux (yes, I know the title of the post is "we need GNU/Linux"). Companies like Framework prove that there's a nontrivial number of people looking for devices like this.
Windows Phone was around during the time that carrying a smartphone on your person at all times was optional, and we didn't have critical government and banking services being delivered exclusively through apps that only work on Google Android and Apple iOS. I suspect that if Windows Phone had survived, and managed to keep even a tiny fraction of the market share, these apps would nonetheless be forced to support it because they would have to account for at least some of their customers using it.
Windows Phone was around during the time that carrying a smartphone on your person at all times was optional, and we didn't have critical government and banking services being delivered exclusively through apps that only work on Google Android and Apple iOS. I suspect that if Windows Phone had survived, and managed to keep even a tiny fraction of the market share, these apps would nonetheless be forced to support it because they would have to account for at least some of their customers using it.