How could you legitimately use the brand name, domain name, or branded social media accounts of a different company?
Sketchy SEO could use it. Or a criminal enterprise that needs a veneer of respectability. Or a business in a country with PR challenges could use the identity of a different company that didn't have those barriers.
But what legitimate things could, say, a US startup do with a defunct YC startup's brand?
Maybe you could do it legally, but wouldn't it be confusing every time you talk with a prospective investor, customer, or vendor?
"Oh, I see the confusion, ha ha... No we're not the Foobr that lost everyone's money, shut down abruptly on their customers, and maybe had to negotiate on their final bills from vendors... We're actually the Foobr that has the resourceful grit to graverob a failed brand. I know, it's a feather in our cap, we're not too modest to admit!"