> Even the combined resources of Amazon and Microsoft weren't enough to overcome this.

Pedantically, their resources were never combined. They independently tried to compete, and they independently failed.

For what it's worth though, Amazon seems to be doing tidy business with entrypoint tablets and FireOS, which is a fork of Android, but still one they own.

Microsoft's exit of mobile was a short-sighted decision IMO. They have the entire office suite. They have windows and Windows has essentially become an app store model too.

I can easily imagine a future where Microsoft leaned in hard on Microsoft Mobile-exclusives for Word/Outlook/Excel/Teams/etc., bundled it with the rest of Office/Windows subscriptions, and had every office worker in the world carrying a windows phone for their work device.

I know, I know - everyone wanted only an iPhone. But it feels to me like Microsoft didn't try very hard.