I imagine both restaurants were making money until (1) the Covid pandemic that put a crunch on sales and (2) they had a falling out among the owners/partners which eventually led to additional money problems.
I know most small restaurants have a small profit margin (I owned one), especially if the rent is high, but their prices and sales should have allowed them to "normally" make a profit.
As for food trucks, the problem is that cities typically manage both the piers and the concessions and will not allow competition to existing businesses. If they reopen these restaurants as new restaurants , it's doubtful they would let competition (other food sources) be part of the mix.