So thesachd, how does one factually determine whether 5.0 is a big deal or not? The bottom line is always money, that's why companies are in business. If 5.0 is a BIG deal it makes users of ios and all the others toss their devices and jump on board. If all it does is allow android to maintain its position it doesn't mean it's crap, it just means it's another nice move up the ladder. And of course everyone has problems with updates, but android is obviously in the worst position to do one smoothly due to the crazy fragmentation situation, and that won't change anytime soon. Unless, of course, 5.0 is so good that it causes all older android users to melt down their phones and buy the latest and greatest lollipop preloaded phones.
You keep jumping from one point to another, which is something I've come to find slightly irritating.
You could easily determine how big an update is with the overhaul that it delivers, for example the update from Windows Phone 8 to 8.1 is a minor one. But the *upgrade* from Windows Mobile to Windows Phone 7 is a major upgrade(though it was on totally different hardware and not really an update in the same sense, but still a good example).
How much phones sell do not reflect on how good an update is. I would argue that Windows Phone 8 was a stellar upgrade but did it magically boost Windows Phone sales? No it didn't.
Lastly Android's fragmentation is as bad as it because of how many people still purchasing outdated devices and those that still own older devices not willing to upgrade. When there are millions, or possibly billions of devices, upgrading them becomes much much harder.
Windows Phone's fragmentation charts would have been more terrible than Android today, had it sold as many devices(especially those from the WP7 era).
Every OS has something great about it, which is why no matter how good one update from an OS maybe, not everyone will switch over.
Basically what I've deduced from your argument is that you mean to say that for an update to be "big deal" it must:
A) Make most(if not everyone) people from other OSes switch over
B) Boost sales by a huge margin.
If those two conditions aren't met, you wouldn't agree that an update is a big deal.
Windows Phone updates have never accomplished either, so would that mean that no update in the history of Windows Phone has been a "big deal"?