[inopinatus]

I'm afraid this perspective is misconceived. I, too, used to believe it. After all, in any portfolio, risk is reduced by diversification, right?

Unfortunately, amortized over the lifetime of a computer system, risk is not reduced in this manner. There is no hedging of vendor vs vendor in a technical portfolio; what happens instead, for any tech of significance, is the internal development of an abstract control plane that can communicate with both, and that control plane is then the single source of defects. In the meantime your engineers have to become world-class experts on two platforms rather than one. In practice the divided loyalties will turn one world-class engineer into two half-assed ones.

Domino-effect failures, or global misconfiguration failures like those experienced by Cloudflare are edge cases in my experience and not something you should optimise for. When they happen they tend to be catastrophic, but worse is the insidious decline in quality caused by carrying too much technical debt.

Cloudflare's scenario is not comparable to the installation of a RAID set. They are more comparable to a developer of RAID controllers. The experience curve for such is very, very long.

Not saying they couldn't have done other things to make this situation less catastrophic, but diversity of core technology portfolio isn't a winning ticket.