Well the obvious answer is training. Medicine requires 4 years undergrad plus 4 years grad plus 3+ years residency. You might argue medicine can be replaced by AI similarly, but the issue is risk. That 11 years is to reach the point you can be trusted to make the really high-risk and high-value decisions, not to do the easy stuff analogous to entry-level software.
Software has been an outlier in terms of its high salaries requiring only minimal training. That implies automating it will disproportionately be both easier and more valuable than many other skilled tasks.