Is it possible to allow sideloading and keep users safe?

> Are you allowed to run whatever computer program you want on the hardware you own?

Yes. It is a basic human right.

> This is a question where freedom, practicality, and reality all collide into a mess.

No; it isn't. The answer is clear and not messy. If you are not allowed to run programs of your choice, then it is not your hardware. Practicality and "reality" (whatever that means) are irrelevant issues here.

Maybe you prefer to use hardware that is not yours, but that is a different question.

Or it's not a computer and really something more like a television. In that case these things should be thought of as a vice rather than a productivity tool.

The social structure of the smartphone app ecosystem is remarkably similar to the cable provider -> network -> show situation from before too.

Increasingly, I keep noticing that all human-corporation relationships are a rehash of older power structures and basically struggles for power in which people gradually keep losing it until they realize they are exploited and then finally start fighting back.

People started free and equal, then some specialized into warriors[0] and gradually built deeper and deeper hierarchical power structures, called themselves "nobles" and started exploiting the "commoners".

At some point people snapped, killed a bunch of them (French revolution, US was for independence, etc.) and decided they wanna rule themselves.

And then companies started getting bigger and bigger, with deeper hierarchical power structures, the "nobles" call themselves "executives" or "shareholders" and the people doing actual productive work are not longer "commoners", they are "workers"[1].

[0]: And thus controlled the true source of power - violence.

[1]: Ironically admitting that people who are not workers are not doing real work, they are just redistributing other people's work and money.