Sure, you need some kind of middle-man as a trust agent, but Google/Microsoft/Apple are not the only possible trust-agents, and their model is inherently biased

Sure, you need some kind of middle-man as a trust agent, but Google/Microsoft/Apple are not the only possible trust-agents, and their model is inherently biased towards certain useful software production models. Let's say I keep bees as a hobby, and I write some small piece of software that tracks and calculates something to do with honey production. I post it to my favourite bee-keeping forum, other people try it and like it, and when a new bee-keeper joins the forum they're often advised by forum regulars to try my software out too. That kind of software can be a huge help to people, but it's not a good fit for an appstore because it's never going to turn a profit, and at least on Apple's store (with the $99/year publishing fee) it'll drain money quite predictably and regularly. A bee-keeping forum will never be trusted by as many people as Google/Microsoft/Apple, but the people who do trust it probably trust it a lot more.