I’m saying that for all practical purposes I never had an issue. That is, I don’t recollect any case where it turned out that someone didn’t get my email. That’s not to say that it didn’t ever happen in cases that went unnoticed by me, but if so it was rare enough to be a non-issue.
No email server in the world can deliver 100% (not even Gmail). Here you are claiming to have done that for 20 years straight. Well, it's not true. In fact, I'll venture as far as to guess that you've never even measured your deliverability.