I don't get why anyone thinks phone manufacturers are not malicious-playing-incompetent regarding updates. So many people are surprised every time their almost brand new phone doesn't get updated anymore.

Why would you trust these people to get software right? Luckily there's LineageOS, a project dedicated to (and pretty good at) not continually fucking it up. The solution is simple: Only buy a phone you can install it on. Stock OSes are full of bloat and malware anyway.