Actually good software engineering is a much larger skill difference.
Based on my years across various companies, the difference between "hobbyist" and "mediocre professional" developer/programmer is close to nil
Also, note that this thread started with a comment about how many developers don't appreciate what the actual hard problems in their own line of work are, and how that produces poor results because of that. I expect that to be true of any profession that doesn't have some kind of rigorously enforced standard.
Painting isn't a profession with a particularly high return on experience. You hire a painter for comparative-advantage reasons. It may take him just as long as it takes you, and several thousand dollars more, but chances are you can make more than several thousand dollars in the time you would've spent painting your house. (If you can't, you may want to re-think hiring a professional, and instead go into business as a painter yourself...)
My parents (not in any way experts on that field) painted their entire house themselves, except for two rooms that were painted by a professional painter, and the professional painter left much worse corners than my parents. This was the paid-for result (ignore the dark corner at the bottom, that’s caused by the flash): https://i.imgur.com/s1VHV2W.jpg