A new street food vendor only competes with other food vendors in the area. A new game developer competes globally, against both established studios and hobbyists happy to work for free because it's fun. You have people who want to make games so badly they'll fight to get in, knowing fully it's low pay and long hours.
Any way you look at it, the reason game developer salaries are relatively low is because supply for the jobs is higher than the demand.
It's a bit silly to compare the two because the economics are so different (local, non-scalable product vs. global product with zero marginal cost), but I stand by my assertion that there's no inherent reason why game developers should earn more, on average, than food vendors.
(not particularly relevant, but I have friends with similar qualifications and experience as you who work / worked in the industry at... shall we say more mediocre studios. I suspect their perspective on this topic is somewhat different from yours.)
I guess the equivalent in software engineering would be someone who can only implement designs and algorithms from other people, and any ambiguities or questions about the design would result in them stopping work until a clarification is received from the "engineer".
The top tiers of any of these industries, however, pay millions. I'm not talking millions because people started their own businesses and got acquired. I mean millions in salary and/or bonus per year, as employees. This is because, as you put it, the supply of extremely talented and skilled workers at the higher tiers is outpaced by demand. (And also because they're hit-driven businesses -- and, absent any real data as to a causal relationship between Superstar A's presence and Supergame B's performance, Superstar A receives the full benefit of correlation).
So you end up with a sort of pyramid structure to the business: lots of workers at the bottom, slightly fewer at the middle, very few at the top, and the compensation flows disproportionately from the top down.
A lot of industries function this way, but the various entertainment industries have especially interesting distributions because they're so inherently attractive to potential applicants.
Where I work we have a good mix of veterans and recent graduates. Typically they are from top North American Universities including Stanford and Waterloo.
Given how fast I've been going through potential (literal) burger flipper cooks at my restaurant, I'm not sure that's totally the case. Some people are surprisingly _terrible_ at a job that many people consider to be the lowest of the low.
There is also a never ending demand for food ;)
You miss the key part of the equation though. More people want to make video games than want to sell street food...
