I recently came across this blog post by David Gordon and I believe it nicely summarizes the problem many C-level executives find with the #NoEstimates agile view. At the end of the day, they need realistic numbers in order for their organizations to make a profit and remain competitive in their markets. It's simply not enough to start development without some sort of upfront plan as to how much the overall project will cost. Gordon gives a nice analogy:
Now, picture a carpenter who has been asked to bid on framing a group of houses. He replies that he can’t tell how long it will take, because his crew hasn’t built that model before. But if the home builder gives them, say, $400,000, they will work diligently, and when the money runs out, they can decide together whether to put more money into the construction. You’re probably thinking that the builder won’t ever do business with that carpenter, and neither will anyone else in town. But that’s because the carpenter isn’t an employee—he has competition. This helps explain why certain software developers think #NoEstimates is a fine idea—they don’t perceive that they have competition.
Unfortunately for developers, this is not a sustainable way of operating - as many organizations continue to outsource more and more positions, developers will need to be able to justify their work as a business case. Gordon argues it's worthwhile for developers to learn software estimating best practices and to "...take some time away from learning the newest cool development tool to become viable as a contingent worker." I have to say that I agree.