Earlier quoted context omitted.
That's an overly optimistic view of things. For a lot of us GitHub is critical infrastructure, which if it goes down loses us and our customers money.
Boomer opinion but trusting third parties to be critical infrastructure, especially with no SLA in sight, will always end in tears. "The cloud" is very convenient, but its providers will never care about your infrastructure or your customers as much as you will.
Github does have an SLA: https://github.com/customer-terms/github-online-services-sla. But like virtually all SLAs, it's really just a token gesture. I have never seen an SLA that pays the losses you suffer due to the outage.