Yes but today there are two centuries' worth of precedent built up around the Constitution that didn't exist in the 18th century, and even then they had precedent from the English courts that they presumably leaned on.

According to Wikipedia, Judge Judy's experience was in criminal and family cases, so she wasn't dealing with the Constitution or even federal law. A nominee for SCOTUS ought to be very familiar with that kind of stuff.

Furthermore, past experience also provides a resume of sorts that allows both the president and the Senate to evaluate a nominee based on their past rulings. Someone whose career is mostly in a TV courtroom doesn't have much material on their resume.