Not trying to be snarky, but Google's policy is as good or better than most (perhaps all? I haven't heard of a better option, though they may exist) and at least they are completely transparent about it. They also have good policies around keeping the bootloaders unlockable so if they do EOL it and you want to update with unofficial builds, that's an option, just not one they officially support for all sorts of obvious reasons.
Nexus has so far been the one Anroid brand that people considering future updates were buying.
The problem with old devices was their lack of power for new increasing computing even for ordinary people (because this industry was infant). But ARM architecture based SoC and embedded CPU will pass (or passing/passed) a threshold . After this threshold you will be able to run ordinary app (I am not talking about high end 3d 4k gaming, I am talking about browsing internet,chatting , reading) for daily usage maybe for 5 year or even more. but your device will become obsolete , because of these thief's . ( I hate how big corporation ripping people off )
Let me give you an instance , you can have a pc desktop with 2gb ram from 2008 . If you are using your device for reading and ordinary job I bet you can install windows 10-32bit (which is state of art) on it and use it without any serious issue . This is the problem with whole ecosystem of Gadgets. Even if you buy a device with tegra x1 SoC(which is powerful as shit) , You should throw it away after 2 year , or you are sticking to old version of android (put aside how much security threat it has) .They can develop a solution for this problem with spending money. But why spending money when they can rip off people ?
I can understand your (and most people) point of view about this problem , but this is not how I encounter with my problems. Personally I am sure non of nexus device (no matter how they will be good) will be my next device . (I am planning to switch device in next month)
The one thing I want to mention and personally I cannot tolerate Google shows himself as savior of us from Microsoft/Apple.But it is not , it is as bad as Microsoft of Apple (I would say maybe even worse than them). I just hate how they can handle media and most people thinks Google is different than any other dirty company out there.
Google literally ripping people off.Google can provide more update to solve the problem(or at least make problem less intense ). But instead they just went to opposed direction. They instead of solving problem. Literally made it harder to solve .
Even the handsets that are sold on the idea of open source have spotty records when it comes to supported OTA updates beyond a year or so after release.
Given the lack of any ideal alternative, I'm personally sticking with Nexus devices and just going with unofficial builds of the OS when it makes sense to do so.
p.s. For multiple times when somebody claimed that , their only references was AndroidPolice site , which I don't give shit about . But seems google quietly updated their policy. (which is unacceptable for me as power user)