The suggestion that they will try muscle you out to maintain their monopoly is a bit alarmist. If you’re not sending spam, and your email infrastructure include

The suggestion that they will try muscle you out to maintain their monopoly is a bit alarmist. If you’re not sending spam, and your email infrastructure includes strong DMARC and SPF policies, then it’s unlikely that your reputation will be tarnished simply because it isn’t part of the Gmail or Exchange Online ecosystems. I’d argue that the vast bulk of email is sent from dedicated providers like Sendgrid which are built on the same tech that might be found in any given ‘artisanal’ on-prem service.