There is only one Google, but there are plenty of bright people who are capable of learning SWE.
If all the little tech companies were making $1m revenue per SWE too, then yes you'd probably see tech wages raise in line with that.
However those little tech companies haven't solved traction and growth yet (if they are aiming to at all), so they can't compete with SV and stay profitable. They don't have $100M in funding to throw into salaries.
Or from another angle - a individual SWE starting their own mini SaaS makes $2k a month. They are happy for this as a start, but on the other hand they are extremely underpaid!
An analogy - shouldn't Amazon warehouse workers be on double what they are paid, as without them Amazon can't ship anything!
At the extreme, workers getting the full value of what they are putting in would be something different to a corp, more like a co-op.
I do agree with the point that many of these firms are operating under monopoly conditions. However, for them to be continue to be monopolies requires them to either hire or acquire the best talent that’s possible. The monopoly cannot run itself, and that’s the leverage that software professionals aren’t utilizing fully yet.
It’s really great for management types that they’ve managed to restrict the median compensation at fairly low levels; this is also the case for software outside of the well known tech hubs.