++ the future of Microsoft Lumia mobile phones ++

• I will think about a comprehensive motivation & at this moment I only forecast that if the company abandons Windows Mobile (so that the mobile platform will not exist), then Goodbye in 10 years also for its role in the PC world //

++ Windows 10 mobile has made one realistic attempt to really scare the competition. In 2015 (a year when Messi won the Champions League) they really provided a challenge (but without Continuum - like Barcelona in the Champions League).

++ the reinforcing effect of Windows Phone on the UWP is significant (e.g. mobile banking apps are disappearing from the UWP, because mobile is important in this field )

++ the slogan of Microsoft Lumia 435 has been "never compromise" & I think with a complete Windows ecosystem the company can afford that slogan effectively in order to promote its value system & vision //

++ maintaining hobby branches shows company strength (indirect benefits are important & also keeping in action the hope, which generates vision & future development)

edit because you added to the answer:

I agree MS are in danger of losing relevance to the individual consumer but that may be a chosen strategy rather than a mistake

• agree with the comment about 2015 and continuum which had a slight possibility of disruption but they were already more focussed on Surface than Mobile. Still not seeing the relevance of Messi to the discussion
• agree that Mobile is one of the obvious consumer facing elements to drive UWP but UWP itself does not need Mobile, companies are always looking for ways to develop for multiple platforms so that code can be re-used and UWP could theoretically contribute in that space but the support model has been weak and too obviously an attempt to bind people to the MS ecosystem with limited return
• marketing slogans like 'never compromise' are a hostage to fortune when this years' 'biggest screen, thinnest device' is next years brick. Apple's 'Think Different' looks similarly weak when you look at the battery and graphics chip issues. However MS are the kings of compromise, usually in favour of the share price at a cost to consumers. Witness the problems with W10 introduction and the instability they caused. If they'd bitten the bullet and 'not compromised' they could have launched a much smaller, cleaner version of W10 and told the market to upgrade if they wanted the 'power' - this would also have had benefits on Mobile and particularly Surface. Unfortunately they had embarked on a strategy to merge the Windows code bases and that means a compromised offering that was flaky and difficult to support
• maintaining hobby branch is a laudable goal (particularly when its me that benefits) but its also expensive and at some point becomes a vanity project, this might be ok in the F1 world where Mercedes performance in a race is not directly tied to sales but in the world of software there's always someone else with an eye on your lunch and vanity projects are far less valuable

It's delightful to see such an exuberant, well articulated, factual viewpoint, on a pertinent issue such as this. If there is any gadget that has become inseperable with our lives, it's a mobile phone. Companies manufacturing these gadgets must start to be aware of that special bond these gadgets, unlike anything else, creates between them and their users. How to handle this, with the gravity it deserves, is yearning at Microsoft.. Lastly, due accolades to Reg.

Best on the Earth meaning MOBILE But not Phone

• what if an improved Windows 10 mobile will be dribbling using skills like Live tiles & Fluent design, with stellar integration with the Windows & Microsoft family  ++ as for new hardware manufacturing facilities, an example could be Goodyear, AZ