shakeel, I can’t comment about Spain, but the same thing happens here in the US. People make offers on bank-owned properties and more often than not, do not get any response from the bank for months. Putting a time-based contingency in the offer does little to move things along.
I believe that banks do this for economic reasons: If banks did start selling their inventories, prices would fall and that would erode the value of the remaining inventories.
Having an undefined process and only allowing a trickle of their home to sale saves face and delays a potential “day of reckoning” for the banking industry.