At a time when surplus capacity exists in many businesses, do/can ‘Lean’ programmes result in substantially reduced operating expenditure?

Prompted by a recent survey - I would appreciate learning your experience?

Did you know that up to 30% of a company's products might be returned by customers? Not just because of faults. For example, a customer (bad customer!) unsure what size will fit her best might order two sizes of clothing from a mail order retailer, returning the item she doesn't want.

Many mail order retailers facilitate this by providing free postage for returns. Neither are bricks and mortar retailers or wholesalers immune from customers changing their minds, and in the interests of long term relationships, will accept returns for credit or refund.

I have noticed that the most commonly talked about disadvantage of the fast fashion model in retail business is the cost of production due to the short production runs. What are the other likely disadvantages? I seem to find this model to assume or rather target people with readily disposable incomes which may make it difficult to plough money back if this group is small. In this context, can lack of disposable income on the part of customers be a disadvantage? What does the group think about this line of thought and what could other disadvantages be?