I will be unable to solve the phone verification because I use LineageOS for microG, but any fraudster can just buy a bunch of $30 android phones. Many people have trouble using a smartphone, so they use dumbphones, but they will be locked out. Many people just don't have any mobile phone because they don't think that it is useful.
Google is mostly interested in abuse that happens beyond the scale of how many $30 phones you can buy.