Is it still worth buying a Windows phone?

Mike is a happy Windows smartphone user and wants to upgrade to the latest operating system. Is this wise, or is the phone going the way of the BlackBerry?

I've been using a Microsoft Lumia 640 for the past couple of years and like it a lot. It works well with OneDrive and other Microsoft stuff, and was excellent value too! Looking to upgrade to Windows 10 Mobile, I see there is no longer much choice of phones. I fancy the Lumia 650 and could splash out on a 950, but is this wise?

I had an Android phone before that, which gradually ground to a halt, and my daughter uses iPhones, but they aren't for me. I'm happy with Windows phones, but what's happening with them? Will they go the way of BlackBerry? Mike