A Shell, especially a dark non-reporting one, has value.
Reasons, not all inclusive, are as noted before...
Management and board members collect compensation.
But, have really nothing to do. No one to be accountable to.
Just keep collecting compensation.

Registration of a new shell is not as easy/cheap as it used to be.
And, shares of the former shell are seldom allowed to follow.

Just speculating on this. Lots of other views out there.