The fact that Google thinks that they don't need to federate with email merely means that delivery to GMail is unreliable.
There is a market-based solution: stop using GMail, and tell clients and partners that you don't expect email to GMail to work reliably.
There is a regulatory solution: require all commercial email providers (i.e. organizations that provide email to non-employees in exchange for money) to interoperate by providing a working grievance procedure for rejection of non-bulk email.
Nobody really wants the regulatory solution, so it's time to widely implement the market solution.
The market based solution will work about as well as telling prospective employers, friends, family, your kids friends etc that you don't accept calls from Verizon. It won't work and nobody will do it.
Your regulatory solution on the other hand appears well thought out and workable.
Can you even tell if a call is coming from verizon? AIUI, in the US, mobile numbers look like any other phone number. (here, each mobile carrier got an 08X prefix where the X was exclusive to them. But you can port numbers instantly, so that only tells you where they started.)
Gmail will mark my outgoing mail as spam if I include a simple link to my personal website. I literally can't email people links to my site if I want to email them from my GMail account. It's insane.
There is a market-based solution: stop using GMail, and tell clients and partners that you don't expect email to GMail to work reliably.
There is a regulatory solution: require all commercial email providers (i.e. organizations that provide email to non-employees in exchange for money) to interoperate by providing a working grievance procedure for rejection of non-bulk email.
Nobody really wants the regulatory solution, so it's time to widely implement the market solution.