> Obviously everyone should default to being a Sheep

This isn't actually that obvious, for a number of reasons.

The first is that it causes there to be more sheep. If you add friction to running your own software then fewer people start learning about it to begin with. Cynical cliches about the government wanting a stupid population aside, as a matter of policy that's bad. You don't want a default that erodes the inherent defenses of people to being victimized and forces them to rely on a corporate bureaucracy that doesn't always work. And it's not just bad because it makes people easier to scam. You don't want to be eroding your industrial base of nerds. They tend to be pretty important if you ever want anything new to be invented, or have to fight a war, or even just want to continue building bridges that don't fall down and planes that don't fall out of the sky.

Another major one is that it's massively anti-competitive. If the incumbents get a veto, guess what they're going to veto. This is, of course, the thing the incumbents are using the scams as an excuse to do on purpose. But destroying competition is also bad, even for sheep. Nobody benefits from an oligopoly except the incumbents.

And it's not just competition between platforms. Think about how "scratch that itch" apps get created: Some nerd writes the app and it has only one feature and is full of bugs, but they post it on the internet for other people to try. If trying it is easy, other people do, and then they get bug reports, other people contribute code, etc. Eventually it gets good enough that everyone, including the sheep, will want to use it, and by that point it might even be in the big app store. But if trying it is hard when it's still a pile of bugs and the original author isn't sure anybody else even wants to use it, then nobody else tries it and it never gets developed to the point that ordinary people can use it.

So maybe the scam we should most be worried about here is the one where scams are used as an excuse to justify making it hard for people to try new apps and competing app stores, and deal with the other scams in a different way. Like putting the people who commit fraud in prison.

> easily able to coach any sheep to do any action

No. This assumption is the core fault with the entire line of reasoning. The typical sheep will not do arbitrary things for a stranger such as sending you his entire bank account because you told him he needed to pay an IRS penalty in crypto to avoid being picked up by the state police who are already en route in 15 minutes.

It's a continuum. The question is how much of the low end needs to be protected by the system.

Binning into discreet blocks to match your example, the question is where to place the dividers between the three categories - nerd, sheep, and incompetent. We don't care to accommodate the third.