According to my Wikipedia research, they had ~2.5 billion in revenue last year and ~450 million in net losses
If they shaved the bottom 25%, to reach ramen profitability they'd need a savings of $450,000 per employee cut, and do that without having any negative impact on the productivity of the org as a whole (be it through hours worked or employee morale or additional churn)
Corporations are giant container ships moving in one direction, you can't just snap your fingers and turn 90 degrees
Soundcloud just had a similar shock happen, and after all the people they had to fire, I would not be surprised if that will kill the company in the mid-term, even with their new investment. If you have no ability to innovate due to missing staff, there is a good chance that your competitors will eat you alive.
Essentially, SC tried to pivot to Spotify, pissed off free users, and let it's actual paying user base stagnate for 2 years.
Then all that capital investment had no return and they're stuck in big contracts with hefty guaranteed payouts.
Twitter is easily overstaffed by looking at what they have produced over the years. Even if you shaved the bottom 25% of employees they could still be operational and extremely profitable. They are a public company, growth is stagnant, and expenses are extraordinary. It's not rocket science even for someone with sheer arrogance and zero experience running a large corporation.