Have you ever worked on a large org with a main product that kept getting updated under the hoods to support more and more "invisible" features that ultimately drive how the product works?
Because if you did you should know that updates are constantly happening...
Twitter's longest standing and most valuable users access it solely via 3rd party smartphone apps, which use an API that's not been updated for many years and have zero new features from twitter in that time.
The service is identical to 2009 or something as far as I'm concerned, and still appears broken as far as video embeds go to this day. It's one of the heaviest and slowest loading sites I can think of.
To be fair, that design and engineering staff took over a year and couldn't deliver an "edit" feature. Project Veritas caught some Twitter engineer on camera claiming to work 4 hours per week.
This is not an endorsement of Elon or anything he's doing with Twitter, but Twitter's core product is not complicated. For some comparisons:
Rumble has 35 employees
When WhatsApp was sold to FB in 2014 they had 55 employees.
WeChat has about 1400 employees.
My guess is you could successfully run Twitter with a few hundred employees.
Internal reps for large advertisers and agencies alone would exceed that number. Long tail advertisers can self-serve, but ad platforms need their whales and whales expect inside reps.
I posit brand ads require more staffing, because they require more sales efforts to get advertisers to buy. Direct response is easier to measure the ROAS, but for brand ads, it's a really good idea to have someone selling ads constantly to your existing clients. Otherwise, many clients in the mid-size space ($100k-$5M/year, approximately) probably can't measure their return, which means those budgets are always at risk of being cut.
With direct response, even data-naive decision makers can figure the value of.
According to Wikipedia WeChat's parent company Tencent had 112,000 employees in 2021. That company has many different products, but where does the 1,400 number come from?
WeChat does push to talk voice chat, image sharing like snapchat, broadcast messaging, video conferencing, video sharing, and digital payments. What is Twitter doing behind the scenes that justifies multiple times the amount of employees at WeChat?
WeChat has always been part of Tencent. It was piggybacking on the infra of what was already one of the biggest tech companies in the world. That's like comparing the number of Gmail employees to Twitter, sure it serves lots of users, but it doesn't have to worry about so much of what a standalone company has to deal with
They weren't making money with those 1000 employees, either. Revenue 10X'd since then (along with cost).
WhatsApp/YouTube were in the same boat when purchased. Good at getting active users but monetizing takes a lot of employees and they hadn't tackled that yet when acquired