1) Microsoft do not have the mindset to do this <snipped> On number 1, all we can have is opinions on the mindset of Microsoft
Nope. We know for a fact that MS' no longer considers consumers to be part of W10M's target market. This isn't just an opinion. It's been communicated in multiple e-mails by MS officials and even been reported on by WCentral:
Perhaps the biggest shift for Microsoft's own smartphone ambitions – at least for hardware – is the demographic. No longer are they pursuing a general smartphone user base, but rather businesses and enterprise.
source
Even without that, MS' utter incompetence when it comes to communicating with consumers should be more than enough proof that consumers aren't their main priority, but that's admittedly only apparent to those who have the time, energy and interest to follow this stuff closely.
your suggestion is that if the phones can run android apps, then no one would write windows apps for the phone. In this you could be correct. But then there still would be a windows phone platform to allow people to also run continuum apps for which android is not substitute. Native windows apps would still be preferred as well.... but that requires there to be enough windows devices out there to write the apps for.
I disagree that supporting Android apps on W10M would result in there still being a "windows phone platform" .
If by platform you mean "the UWP", then no, because you'd be removing a big reason for many developers to target the UWP at that particular form factor in the first place. That's not contributing to preserving the platform, but working towards killing it.
If by platform you mean "ecosystem" and "relevant user base", then again no, because those are already gone and they won't be brought back by offering the ability to run Android apps on W10M. People already have a gazillion cheap ways to do that, all of which will work better than running those same apps on a similarly priced W10M device. The only people who care about this are the 1% still trying to justify staying with W10M. It's not worth sacrificing UWP's developer appeal, for now and evermore on phone-sized devices, just so MS can continue selling phone hardware to those 1%.
IMHO you're still wondering how MS can entice consumers (a.k.a you, me, and most other here) to stick with W10M. They can't. That's over. I'm not saying that can't ever change. If MS fires the product managers responsible for W10M and finally decides to do something with the OS that people find exciting, then they can still turn things around. As long as MS has money to invest in W10M development it's never to late for a comeback, but at least in it's current state, particularly when it comes to consumers... forget it...
The one thing that is certain, is that if W10M ever does manage a comeback, it won't be by introducing the ability to run apps everyone else can already run. W10M will never achieve success by being a better iPhone or a better Android device. That ship has sailed. It must either develop into something new and different and exciting, which people wouldn't instinctively compare to other smartphones, or die.