Yes, just as it is possible to practice most other fields on a day to day basis without a current command of the original foundations. Besides, constitutional scholarship is not really a foundation of legal practice, most of which is derived from English Common Law Practice ammended by statute passed by state legislatures. Most practice avoids constitutional issues altogether.
Yes, precisely.
Practicing lawyers never get into THE BIG PICTURE questions. The Supreme Court is precisely where those THE BIG PICTURE issues are argued and they depend upon a solid grounding in centuries of law.
Rokke, you can fly a plane. But can you design one ? That is what a judge does as opposed to a lawyer. Can you create THE BIG PICTURE ?