The perfect theft in crypto is claiming that a project or an exchange is hacked when its all an inside job, the reason why I think about this is I have never heard about other top exchanges helping a exchange that just got hacked to track their funds and get some back at least but if it's a sole hacker from outside they will track him or them down, why is that?.
There are instances where there was an inside job and there are instances when exchanges helped in returning the hacked funds, so it is not like none of the exchanges will help in returning the funds but there are hacks which were dubious to begin with and the funds tends to be mixed using a mixer before loosing the trail and in those instances it is really difficult to track.