mutliple CDN as well
As a dyn customer for about 9 years now(across 3 different companies) after the attack struck some providers tried to get me to go multi provider. To me does make sense but only really when it is also paired with a multi CDN deployment as well, and for whatever reason I don't see nearly as many people talking about that as multi DNS deployments.
DNS also has made it easy to use multiple providers forever now with slaves and longer TTLs. Though if your all up in their APIs and stuff then that may make it more difficult.
For the org I am with and probably many others this one outage was not nearly enough to switch off of Dyn(or to go dual provider). It's still the most reliable service I have ever used, and as a bonus their UI hasn't changed in as long as I can remember (probably in the 9 years as a customer). Which is refreshing for once to see something stable.
If only other cloud providers could tout 1 outage in 9 years (certainly is possible dyn has had more than that though nothing that has registered on my monitors long enough to be detected). They seem to be very proactive about alerting customers with https://www.dynstatus.com/ -- one of the first public status pages I can recall coming across.
All of the DDoS attacks that have affected me have always been collateral damage, either attacking Dyn in that one case, or in several other cases attacking upstream ISP (which in itself has probably 8 different load balanced proivders). CDN we currently use hasn't had an attack big enough for us to notice but they aren't a big name player either. I have seen more than one article in the past about big outages due to attacks or something at Cloudflare for example (don't recall anything recently though).