I replace air conditioners all the time - sometimes just because I want a more energy efficient system. Sometimes the landlord just wants a new "Reliable" system, that they will not need as many service calls on it.
Usually commercial building owners want to replace a 20 year old system to increase reliability, and also to keep tenants happy. So maybe it is time to let someone repair your old Excursion that can do the work themselves, low cost labor and taking time to rebuilt it themselves.
Yet some say "Put in a new motor" and spend a lot of money to basically restore a unique truck like yours back to like new condition. They don't mind that they are spending $8,000 on a vehicle that you can buy another older one for less. They just want it that way.
I know a guy who put about 800 hours labor and $5,000 - $10,000 into a 1966 Econoline pickup. He put it on a 3/4 ton truck frame, made it a tilt cab, installed a newly built (by him) 460" engine and transmission. He claims it is better than a new truck, with $35 registration, and no sales tax (well except for the new parts he installed). In California a new $25,000 truck would have had a $300 plate fee each year, along with inspections, and more.
Fred.