I can't help but wonder if this is a reflection of Digital Ocean's target market, and its late adoption of block storage and other functionality. Kubernetes is a pretty "serious" tool, and you'd expect "serious" teams to have a preference for bigger, more-established players like AWS/GCE. Digital Ocean having been moving up the chain but at least in my mind they're still associated with the "hobby site" mindset. Certainly I run my hobby sites there!

I wonder if a similar survey from the bigger players would have different results.