Big companies are amazingly efficient, just not in terms you consider. They earn way more dollars for each dollar spent than smaller companies. They can do that by having income sources beyond wildest dreams of smaller companies. That's the reason they got big in the first place.

And why from the point of view of footsoldier things don't look as efficient as they could be? Because they don't have to. Because inefficiency you see is negligible and trying to eliminate it could cost more money than it's worth. Heck, some income streams are larger if you work slower than you could. You could be harming your bottom line by making things more efficient.