Founder mode existed, it just didn't have a catchy name. And I absolutely believe that it was the right choice for your team, exactly for "founder mode" reasons.
In other words, I don't think that the social or technological reasons in the document were that strong, and that's fine. Rather, my external armchair impression is simply that OS and hypervisor were not something where you were willing to spend precious "risk points", and that's the right thing to do given that you had a lot more places that were an absolute jump in the dark.
I would agree with that. Given the history of the Oxide team, they chose what they viewed was the best technology for THEM, as maintainers. The rest is mostly justification of that.
That's just fine, as long as they're not choosing a clearly inferior long term option. The technically superior solution is not always the right solution for your organization given the priorities and capabilities of your team, and that's just fine! (I have no opinion on KVM vs bhyve, I don't know either deep enough to form one. I'm talking in general.)
In other words, I don't think that the social or technological reasons in the document were that strong, and that's fine. Rather, my external armchair impression is simply that OS and hypervisor were not something where you were willing to spend precious "risk points", and that's the right thing to do given that you had a lot more places that were an absolute jump in the dark.