you totally miss the point. 
By taking floor space from unsecured and moving it to secured, you have NOT changed the amount of money that will be spent. In fact, you may actually LOWER the over all amount since now, you have removed a number of customers, and created NOTHING to provide incentives for passengers to arrive early OR stay longer on layovers. 

And no, building out the concourse will not be cheap. Of course, neither would the concourses, BUT, they would pay for themselves. OTOH, day's approach does not pay for itself, it just grabs money that was going to the airport and sends it overseas. THat is exactly what the airlines,who have been doing this for almost a century, object to Kim Day's approach.
In fact, I have written Airline executives that I know ( I grew up in the Air Force and Airlines) and am seeing movement from them on the idea of concourse D/E idea.