In your reasoning, "most" users would be done and "most" apps would be malicious.
But in the end, it's quite simple - dealing with power use on mobile is hard and most developers don't care (same as they don't give a crap about making your web pages fast and slim). Users care about battery life above most of other features, including your freedom. They WILL got and buy a device that lasts the longer amount of time in the smallest and lightest package.
As long as these two things are true, leaving developers to run their polling code without restrictions has a massive effect on sales of both OEM devices and Android ecosystem as a whole. As such, OEMs are actively modifying Android to not allow this - see the wonderfully depressing https://dontkillmyapp.com/ - which is a significantly worse mess than you having to use a proprietary service to send a single device wakeup ping.