None of those are "round robin DNS" as mentioned. None of them are "fairly easy."
And yes, being more precise is necessary when you are critiquing someone.
And yes, being more precise is necessary when you are critiquing someone.
Yes, certainly there are other options that increase the complexity, but why not start there? While the impact to users on shitty ISPs or behind proxies is unfortunate, it is relatively easy to implement and low-cost.
Going beyond that increases the complexity and cost exponentially and is certainly not easy.
Unfortunately some stupid resolvers cache a single answer set for a long time, but for some applications, you're willing to accept 1/x of attempts fail during an outage (just hit reload, or come back in a bit), since this costs ~nothing to implement.
The basic concept works great for NS, MX, and other protocols where they're designed to retry.