It's been awhile since I was in a big org, but when I was, no one was replacing laptop parts. The deals we had with Dell/HP were basically overnight replacements (this was different from servers where we had 4 hour on-site support). Then we would send them broken machines that would eventually come back fixed.

So do big orgs actually have people internally swapping random parts in a laptop to see if they can fix it?

Doesn't change the point that Apple was more expensive, but mainly because Dell/HP prices go way down at volume.