It's probably temporary? Move to R53, then figure out what's needed to manage records on two providers (if only for internal processes). Top engineering teams aren't going to knee-jerk this, right? Or did Dyn show some unfixable incompetence?
I don't think Dyn showed any incompetence; the parent-poster was merely remarking on relying entirely on a single provider, who, if they get DDoS'd, causes your site goes down. (There was some previous discussion about splitting between providers, but some commenters noted that it was difficult, or at least non-trivial, to replicate records between two providers.)
Lucky for Route53 users, Route53 DNS surface is really large and there is a really good chance that not even is attack could hurt it.
Aside: I came out of college as a sys admin with a CS degree and writing tools like this was par for the course. If devops folks aren't writing tools like this today, what are they doing?