The question is not the skill involved but the artificial cost of entry imposed by three years of law school, bar exams, continued need to pay fees, exclusion of ability to practice in states even if you are qualified in another state, and a range of other guild-like rules used to raise the market cost of legal advice above what the market would bear. While some parts of legal work clearly need the full expertise, large chunks of it require and are done by paralegals and legal secretaries-- but where you need a lawyer signing off to raise the cost. Assuming legal malpractice remained a viable punishment for those giving inexpert advice, there would be pressure for decent expertise even without the formal credentially guild.
It is true that many professionals are largely insulated from the global market forces that ordinary manufacturing workers are buffetted by under NAFTA et al. The proposed GATT could change that in some rather dangerous ways, but it's probably accurate that one reason why there is such a large "free trade" consensus among liberal professionals at odds with working class folks within the progressive movement is that different vulnerability to global competition in many professional skills.
-- Nathan Newman