Maybe they mean experience writing for other companies.
That must be it. But I can assume there's not much difference about how companies operate. That is, writer can see instructions and deadline and his/her job is to delivered the order on time.
someone with many years of experience writing (literally) thousands of essays is likely to be much better at this than someone who has never done it for a living before
I sort of agree. But on the other hand writers who have written thousands of essays may get a little lazy as time goes by and copy-paste already used parts. I hope it doesn't happen too often :)
