It has been relegated to a corner because it is generally viewed as an approach divorced from the market where rent and price rule. Some would say yes. Others would say not necessarily. In another, the only relevant method of valuation is by sales comparison. We go back and forth.
Cost is good.
Cost is bad. We are like the dog that has a ball in her mouth but that also wants the ball on the lawn. To get the ball on the lawn, she needs to let go of the one in her mouth. Much as she may want to, she can't hold them both. Little wonder that appraisers back off from application of cost analysis when they know that it may amount to little more than an academic exercise.