A strip mall (or any mall for that matter) is a collaborator in that the businesses, through a management company / owner / landlord, share costs. From the parking lot, to the signage, to the walkways (common areas) - a cost sharing collaborative is taking place. The businesses share more than that, they share customers; the customer may come for one specific purchase, but see all the other "opportunities" (other stores). It is why businesses like to rent where there is a popular "anchor" store (like a large grocer); because they can ride the coat tails of the anchor and collaborate as a larger force.
Collaborating is much more than good business, it is business.