Eh, from the company's perspective this is logistically easiest--the laptop's value is hardly worth the effort.
We always let our ex-employees keep their laptops because a. why not? and b. I don't need laptops for positions that no longer exist.
And yet only one company I've ever worked for went this way.
I wish more did; it really is such a small goodwill gesture to departing employees.
a lot of companies ask for equipment to be returned due to security concerns, or just on principle