A Twitter employee took down Trump's account for 11 minutes
businessinsider.com
businessinsider.com
For "celebrity users", it's more scalable and necessary.
Everyone is probably logged into their employee account, and on that scale, I would think Twitter would have everything logged, so they know exactly who did it. But for accounts marked with "Celebrity Status", I would have thought they had something in place that blocks their "regular employees" from being able to delete those accounts without approval, and it must go through some approval of a higher-up. So it is definitely scalable in regards to celebrities, even though there are hundreds to thousands on Twitter, I'd think if I was running Twitter, I'd have just a few select who could actually delete celebrity accounts. After all, it is those celebrity accounts bringing in the most page views.
Hell, I can't install anything on my computer at work without getting administration approval from the IT guy. All email outside of the work email is banned, simply blocked, to protect the data. We work with highly sensitive data, so all applications installed must go through an approval process, submitted to the higher ups, reasons explained for the need of the application, what it is, and why it is being used for work purposes.
So to delete a celebrity account, I would think they would have had similar measures in place. Reasons for deleting the account, approval process, etc.