1. People are conditioned to ignore warnings. There are way too many benign warnings in the world; you can't read them all.
2. Even when people wouldn't ignore them, in cases where they are being tricked by scammers it's easy for the scammer to talk people into accepting them.
3. Those sorts of warnings aren't actionable. You're installing a new app. It appears legit. You want to use it. You get a warning like "this app hasn't been verified; it might be malware!". What can you do with the information? Absolutely nothing. 99.9999% of users have zero way of doing any deeper check to see whether it actually is malware. Their only options are to give up and go home, or just hope that the warning is wrong. Even I - a highly technical user - get zero value from things like Windows' smart screen. "The app you're running hasn't been signed! It might be malware!". Err yeah sure. I'm not going to reverse engineer it to check am I?
I think their solution of allowing you to disable the restriction with a one-time one-day delay is actually a really reasonable solution. As long as they don't go further than that - the risk is that it is just a temporary placation and they'll ditch that option in a few years.
You can't possibly convince me that Google couldn't develop something like that if they wanted to.
You could probably restrict "risky" APIs like draw-over-other-apps, but tbh I think that would be a worse solution than just making people wait 24 hours once.
How do you determine/enforce whether an app is a "payment app" without a centralized developer program? They don't require any special privileges. After all, most banking apps have web equivalents.
We can't keep catering to the lowest common denominator of user. We have lost many computing freedoms over the decades as a result of this. Sorry, but its unacceptable.
If they really want such locked down experience to be the default, they could also just as easily put out a ROM everyone else can flash that has no restrictions. You still get to cater to the lowest common denominator but without taking freedoms away from anyone else that wants to keep them, with official support. No scammer is going to convince someone to plug their phone into their laptop and flash a new ROM in order to scam them. If they can, there's no protections that would have helped in the first place.
To be clear, enough does not mean that will stop every trojan/scam. People send Starbucks gift cards to callers claiming to be from the IRS calling to collect overdue taxes despite the obvious absurdity. Enough means that someone who doesn't know anything about computers but who reads and believes the warning label has sufficient information to know that it's a potentially dangerous decision. Some people will make the dangerous decision anyway, but it's on them at that point.
Neither approach are going to be perfect of course, but I would expect the current system to be nearly useless and the 24h delay to be very effective, and it seems like a very minor inconvenience to most users.
(All of that is caveated on this not being the start of a slippery slope, which I wouldn't bet on.)
That's the same reason why desktop computer has so many malwares, that's why phones now has permission systems to restrict what an app can do on it.
If you want to create a system for everyone, including your 60 years old mom and her mom, you need similar of not better permission systems. Linux currently don't have that, and DON'T except an old fashion car mechanic will delicately configure AppArmor etc with his oily fingers in the middle of fixing a client's car.