My guess is the old man stuffed them over in the corner because there were no available buyers not because some unforseen incident 5 years hence might require them.
There is the matter of cost. A certain amount of hull insurance may be neccessary. Do you pull them out peridically and exercise them or just let them sit? If you exercise them - another expense. How about crew training? Do you keep crews current or just try and get them up to speed when the aircraft are pulled out of mothballs?
Remember in business you spend a dollar (or euro or pound) and hope to earn say $1.10-1.25 in return. You save a dollar and you just earned a dollar.