Early 2000's for me, and yes, similar experience. What was really interesting to me is that my home domains had no problem emailing my work and side bit gmail based mail service a few weeks ago. Then, suddenly, this stopped working.
I changed jobs as well, and now work is using a MSFT based hosted mail service, and I am getting delay messages.
Seriously, GOOG, MSFT, and others broke mail. This is not an improvement.
I've not looked into speaking with MSFT mail folks about their breakage yet. With GOOG, you have really no mechanism of reaching out to someone there and getting attention for the problem they are causing.
This is the much bigger problem with GOOG actually, in case any googley people are reading this. They just don't get customer service. At all. It is near impossible to be able to report a real problem across the spectrum of their services. Unless you are one of their bigger customers, you don't have access to even a telephone support number. Their online help is a crapshoot, with you getting useful information less than 50% of the time.
So where I am now is with locked down, long time existing domain mail servers, which send maybe 5-10 outbound messages per month, that suddenly and inexplicably, have a bad reputation. Well, no they don't have a bad reputation, they can send email just fine to other services.
That's a great idea. I've run my own mail servers since 1999. I'd happily join a union of independent mail operators with the purpose of lobbying Google, Microsoft, and Yahoo to treat us as first-class citizens.
I think you should have a web page where you list your issues, show how you've done all the normal things to be considered a well-behaved mail domain. And then perhaps report your experiences with iinteracting with gmail support on the matter.
Even if it isn't deliberate, even if gmail give a fuck, as can be seen from the first (and so far only) response from anyone at Google, they're so far in the Google "We're better than everyone else and always get it right because we're geniuses" RDF that it literally doesn't matter. They can't believe that they're the problem.