I second the view of this post. Real world experience counts a great deal in the practice of law--especially 25 years' worth. A lot of cases involve constitutional questions and are litigated by attorneys other than "constitutional lawyers" so the idea that only constitutional attorneys are qualified to deal with constitutional questions is simply not true. I can't think of a single course at law school that didn't involve significant constitutional issues to resolve.
A lot of so-called constitutional attorneys either teach primarily and consult on constitutional issues on the side, are government attorneys, or practice in that rarified atmosphere where they might handle two major constitutional cases a year. Most attorneys are "veterans" if they have handled four or five Supreme Court appeals during their entire careers.
Actually, the vast majority of lawyers, even many of the very best lawyers, NEVER argue a case before the Supreme Court. Unless a lawyer works in the Solicitor General's Office (the main function of which is to represent the Government in cases before the Supreme Court), the Appellate Section of the Attorney General's Office in one of the larger states, or in one of the handful of appellate litigation botique practices in Washington (which is what Chief Justice Roberts did), the odds of ever winding up before the Supreme Court are miniscule. In 33 years as a litigator at a large law firm with a sophisticated trial and appellate practice, I have had exactly two cases where a party filed a petition for a writ of certiorari (a petition asking the Supreme Court to hear an appeal). Both petitions were denied. I have argued plenty of Constitutional issues over the course of my career, but I suspect I will retire having, like most lawyers, never having argued in the Supreme Court.