Don't you end up with the same problem with the automation that has been running fine for 5 years, then suddenly breaks? And the person that set it up is either gone, or has no clue how they did it 5 years ago.
Recently saw a (thankfully not mission-critical) old k8s cluster fall down with absurd incompatibilities between node versions, cluster versions, and cert-manager versions - all of which only support upgrades one version at a time. Even infrastructure-as-code doesn’t save you if you need to upgrade something but don’t have the time and expertise (and esoteric changelog knowledge!) to reliably upgrade everything else.
Before LE almost no one automated SSL cert refresh. Depending on your SSL cert vendor you couldn't automate things even if you wanted to. It's not that the automation ran fine for five years, it's that you'd be lucky if the manual process last done 5 years ago was even documented.
SSLMate is about as old as LE, they both started around the same time.
Every 6 months? That seems like a pretty long window for tribal knowledge to get lost. Is 6 months arbitrary or is there some reasoning behind that cadence?
That's an amazing amount of effort expended on something that provides exactly zero revenue. I understand the concept, but I've never been fortunate enough to work in a business where that was practical.
LE by default successfully ran 2 months prior. 2 months and 5 years are two completely different worlds in terms of bit rot. That and there are many generic tutorials and scripts and knowledgeable devs for configuring LE fresh.