A lot of as in "a quarter of a million a year for a few years running"? I doubt it, and I guess that may not even be what they would need to make it a successful product at their scale (by my counting on apple.com, they now have 6 different notebook form factors and 5 different desktop ones, and Google tells me they sold over 19M Macs in 2014)
Add in that most of the 17" models sold likely would cost them a sale of a smaller one, and I doubt the numbers would add up for them.
But I love the new rMBPs, and I suspect more pros enjoy the weight savings, battery life, and fantastic displays than are irked by the lack of an optical drive.