That's absolutely fair, and 1/300M was a reductio ad absurdum rather than a serious proposal. Not all users are equal, just like not all lines of code are equal :)
I have a few issues with the "hot user" theory, but they all boil down to the same point: no matter what the use case, you'd never want to do this with a single static user.
Does your infra require special-casing for accounts with more than 100M followers? That should be a flag in the account properties that gets flipped manually or automatically: if these users cause infra problems, you really don't want to be making code changes + full rollouts whenever a new user becomes hot.
Is this just a guard-rail metric, to make sure there's not some bug specifically affecting hot users that tanks their engagement? You'd want a much larger static set than a single account just to ensure there's a large enough number/variety of tweets to compute metrics from. A single user might take a break for a week, or might only be posting very specific kind of content for an extended period of time.
In any case, even if you chose to do this with a single user rather than a set of users, why would Musk be the obvious single choice? He wasn't the most followed Twitter account until two days ago. A year ago there must have been at least a couple of dozen accounts roughly as notable as Musk. The odds of him having been chosen as the special case still would not be very high.
> In my view there isn't a compelling reason for him to lie about this.
The reason to lie about this is that it makes him appear weak, needy, and a target of even more mockery. Given the purchase of Twitter seems to have been a vanity project, having this be exposed and leaving it in goes directly against his apparent goal.
