I agree it is a cost versus space versus profit versus number of sales. But if you look at it from Ridgid point of view. HD is their exclusive retailer now that the products are not on display where does a person go to see them.
I think you highly overate Sears, in my neck of the woods their reputation is in the gutter and the fact that bankrupted K-mart was able to buy them I would say that reputation was probably true everywhere.
At one time nearly every garage had a Craftsman tablesaw or Radial arm sitting in it. Today only those that don't any better buy from Sears.
Ridgid and HD were in an excellent position to have Ridgid tools in every garage until HD decided they were going to follow Sears marketing practices and Ridgid allowed them.