As with every other "simple solution" to a complex problem there are a few flaws:

a) google will have to require a credit card in order to open an email

b) person opening an email account must actually have a line of credit, e.g.: many of the people mentioned in the OP will not have it

c) opens a new attack vector on google accounts, e.g.: people who secured their emails using 2FA app for example can now be attacked via a credit card process