I think it can and does work, but that doesn't mean it works for everyone.
I have an iMac (as noted in my earlier post in this thread), but I find myself in windows more often then not it seem. While I see the advantages of a single platform/ecosystem. I believe Apple's direction and implementation on that ecosystem may be the result why you don't think it works.
I have an iPhone, and at this point, I don't see myself or my family leaving that platform, I have my Mac but I'm also looking at a SurfaceBook for my mobility needs. I think picking the best tool for the job is better then just picking based on the fruit logo on the outside.
I'll agree with you on that it can work for some not for others, I'm definitely in the 'others' category and I'm finding a mish-mash works best as no single eco-system has it all (at least for my needs).
Apple's fell short for my uses but it was not all Apple's fault the biggest driver was compatibility with works software and whilst I initially boot camped (even had parallels), the drivers were not always the best and the fans, trackpad and battery life became a frustration and then the Surface was announced which was the product I've been waiting for.
I jumped back to M$ eco-system buying: SP2, Lumia 1520 and Xbox One with Onedrive and OneNote this was all brilliant and suited my productivity needs, but as you know WP10 is in declining and unless this Surface phone is a beast (if it is even released) I'm having to break the eco-system and get a IOS or Andriod phone, this is easier as now M$ is making good apps for office, OneNote and Onedrive on other devices.
The phone that currently ticks all the boxes for me is the expensive Note 7 but I'm waiting on the wearables (gear 3 vs Apple watch 2) to make my final decision as for me Apple have the better overall leisure setup and I'm happy to go iPhone +, watch 2, Apple TV and Ipad combination as those devices work well together.
When it's all said and done it could end up as
M$ SP4 or SP5 (main computer)
Note 7 and Gear 3 or Big iPhone + Watch 2
Ipad, Apple TV, ITunes - Leisure