then people feel as though it should get those updates for more than 3 years

People? Or just a very small minority on /r/Android because I'm pretty sure it's just the latter.

Seems odd that it wouldn't get software updates anymore after 3 years when in fact it can handle the updates just fine.

Not really, especially when it received what was previously stated it would receive. Expecting more after it's already received more than it should have is essentially the definition of entitlement.

Whether it can handle the update or not is irrelevant. Releasing it would be a waste of resources, not too mention a source of headaches later. Because when you do it for one you'll have to do it for another. A year from now you'll have people complaining that the Nexus 5 has had support officially ended.The Nexus 6 the year after that and so on and so forth. There will be no pleasing people once you cave to something you already did them right by in the first place.

But to be honest I honestly don't care. I sold my N4 two years ago and I genuinely don't feel like doing a back and forth with anyone who is incapable of understanding they already got what they were promised and then some. You don't deserve more. Hardware. Software. Whatever you wanna call it, you already got what you were told you would plus an additional year's support on top of it. At no cost to you. That's not something that happens and you can't provide a single example to support why you should get more. "Windows updates" and "Apple does it" are not comparable on the same level. Not by any means.

So I bid you good day and good luck with your N4 or whatever you're using. Feel free to discuss with anyone else, but I'm done here.