The reality in South East Asia doesn't support that. You're assuming that the potential victims are able to either use Android alternative or that they are willing and able to educate themselves about scams. The reality in these countries is that neither is the case in practice. Daily lives depend a lot on smartphones and they play a big role in cashless financial transactions. Networking effects play a big role here. Android devices are the only category that is both widely available and affordable.
Education is also not that effective. Spreading warnings about scams is hard and warnings don't reach many people for a whole laundry list of reasons.
The status quo is decidedly not fine. Society must act to protect those that can't protect themselves. The only remaining question is the how.
Google has an approach that would work, but at a high cost. Is there an alternative change that has the same effects on scammers, but with fewer issues for other scenarios?
The status quo may not be perfect but it is the best we can do. We try to educate people about scams. We give them warnings that what they are doing can be dangerous if misused. If they choose to ignore those things and proceed anyway, the only further step society could take is to take away the person's freedom to choose. And that is an unacceptable solution.
Society takes away individual's freedom to choose all the time. You can't choose not to pay your taxes. You can't choose to board a passenger plane without passing a security check. You can't just get a loan without any guarantees to the bank etc.
Education isn't really working at this global scale. It doesn't reach people the way you seem to belive it does. Many, if not most people are generally disinterested in learning new things and this gets amplified when it involves technology.
The original post laids out why it's not possible to do well: privacy apps, sanctioned countries, apps made by people for themselves to avoid clouds and third parties, etc.
Simple example: I have a foss VPN app running on my phone to avoid censorship and surveillance in some countries I visit. While using this app is no problem, non-anonymous development might carry consequences to the developer in some dictatorship jurisdictions (which are plenty of). I'm not sure all devs of such system would be willing to give their ids.
Another example is that this way US can cut out countries and people they don't like from mobile usage (which basically equals to modern social life). Look into sanctioned judges of international court because US protects war criminals.
Education is also not that effective. Spreading warnings about scams is hard and warnings don't reach many people for a whole laundry list of reasons.
The status quo is decidedly not fine. Society must act to protect those that can't protect themselves. The only remaining question is the how.
Google has an approach that would work, but at a high cost. Is there an alternative change that has the same effects on scammers, but with fewer issues for other scenarios?