Reading through the comments, almost everyone missed the elephant in the room.
The big problem with long term support is not on the phone or chip manufacturers.
...::: It's GOOGLE! :::...
Just compare the history of Android with Windows. Windows 10 is still supported for another 2 years, yet it was released in mid 2015.
Every Windows 10 capable device is still receiving updates till then.
Contrast that with Android.
Android 6.0 came out in October 2015. Yet very few devices from that era are supportable today. Why? A large part of that is based on Google's never ending -> breaking changes <- and random new requirements that make older devices incompatible.
This got me personally when I bought a Sony Z3 with the intention of having a "future proof" phone. It was openly advertised as being a dev device for Android 7, so much so that a preview release was downloadable for it.
Only for Google to drop a new requirement for the GPU to have minimum OpenGL ES 3.1, while the GPU only had the instructions for 3.0. WTF?! I might add, the specification for 3.1 was only released to the public 2 years prior.
I seriously hope that some alternative to Android will establish itself again. We had Windows phone, which Microsoft utterly butchered. IOS is not an alternative as that's tied to one manufacturer.
Yup. While I have a sceptical opinion of Ubuntu, it did find it sad that it didn't gain any traction.
A possible contender is still Tizen OS. It's essentially an entire OS build around Chromium, while not owned by Google. Samsung use that a lot in their smart TVs.
Sure, it's not as performant as running native Android.
But boy have we seen some massive improvements in browser tech and performance increases on mobile devices. Developing web-applications is certainly a ton easier than native Android and IOS. Wrapper toolchains like React Native aren't helping much.
Unless you really need calls to some device APIs, there isn't too much left that a Browser can't do compared to what the native OS permits. I've been developing web-apps for robots and also developed equivalent native apps in Android. In the browser you now have access to some impressive 3d capabilities, which are extending further (BabylonJS). You've got the ability to interact with files via tool-chains that are not too dissimilar to what you see in native Android (Google has been clamping down file-system access to app devs quite heavily in recent releases). You can also gain decent API access to the devices battery and GPS status. Add some nifty UI libraries and you can provide a more pleasant experience, faster than with an actual native app. Even video streaming works remarkably well since you can interact with multiple cameras, microphones and even the screen (Google Meet does that).
It's now that we're seeing PWAs (progressive web app) to gain traction. I'm using Voyager for Lemmy, which works lovely in Windows and my phone.
In the browser you only miss on some native capabilities on some hardware component and a few legacy systems. Mainly serial communication and native UDP support. Although the last one will see some more improvements with HTTP3, which is gaining traction.
The one thing I wish google never did was introduce SafetyNet without enabling us a way to essentially say "I modified my own phone, so let me use my damn banking and tap-to-pay apps without issue" and reenable it.
In fact they've actively made safetynet more invasive by adding CTS profile matching alsongside basic attestation, with a system for telling what phones are compatible with the new profile matching so you can't force disable it.
If they never added that I could've bypassed basic attestation and gotten google wallet back. But no. The most I can get back is banking and Pokemon GO. But there's still a risk one of them will decide to use CTS and therefore making it impossible to use that app on my current phone, all in the name of "security"
It's my phone, stop trying to smother my attempts to do what I want with it!
i use e/os, that replaces like everything google has like the google micro services with something else. Some apps, newer ones with more trackers, tend to break but it supports some phones from 2013. I suggest taking a look when you have phones that are not supported anymore
It seems to support Sony Xperia Z3 https://doc.e.foundation/devices