> If a domain's authoritative mail servers have a history of never sending spam, when that company or hobbyist (for any reason) has to switch hosting providers and gets a new IP address, Google/Microsoft should recognize that the domain, and its referenced mail servers, has never been malicious.

That algorithm doesn't work. The internet is filled with parked domains that have "never been malicious". This just creates a new market for clean domains that you can use to evade protections. It makes spam a little more expensive, but it still gets through.

None of these tricks work. There are no tricks. All rules can be gamed. The only thing that can't be easily faked is reality: if Microsoft knows you're a big org with a well-managed IT group running your output email setup, then they know they can (probably) trust you not to spam their customers. If you are too small to prove that to MS in a scalable way, no amount of heuristic trickery is going to help you.