Also, "How does Company X have Y engineers? What do they all do?" Is one of the most common and annoying comments that constantly appear in HN threads.
If you've been in the industry long enough you have experience and you get at least a feel whether x engineers seem a lot or whether y microservices seem a lot.
Now in this case we also know that Musk has cut half the workforce so, rightly or wrongly, he has concluded that there is a lot of bloat at Twitter (not 'some company'). I can only take this as a significant piece of evidence as I don't know Twitter.
More profoundly I think this has been a consequence of the cult of 'growth'. You have to show that you're growing so you have to grow the team, you have to keep hiring and justify it by 'growth' because if you don't your company will look badly in itself and compared to peers, your IPO will not be so great, your share price will tank. Once you're down that rabbit hole you're stuck. Maybe younger engineers who have only lived professionally through this period actually believe the hype.
So I think the current wave of tech lay-offs is partly caused by this no longer being the case so that companies can be more realistic and cut bloat without fear of being seen as a lame duck.
Of course a bloated number of engineers means bloated software because all those people were busy doing something, may something not useful at all but something (including perhaps thousands of microservices...).