You don't need to accurately assess it to be surprised they still have a lot of employees. They don't seem to do much anymore that is visible. Quite a long time ago they were a leading company. I have no idea what they even do anymore.
I would read his comment more as "I didn't know the company was still so big" than "wow how stupid are they that they didn't fire all those people years ago"
there are more inscects in a cubic mile of rural land than humans on earth. are you surprised?
Humans in general are horrible at encompassing large numbers. We can interpret and understand them, but our mental model sense of scale isn't flexed often enough in daily life (where we maybe deal with thousands at most) to truly appreciate hundreds of thousands, or millions intuitively.