I'm not sure I understand your point. My point is simply that those 10% are better able to capture the value they create, whereas the bottom 90% are not. I'm not making any assumptions about a fixed-size pie.
The point is, those 10% aren't better able to capture the value they create. They're just in a more favourable position from the perspective of the labour market. It doesn't mean that the fact that they are 'knowledge workers' is giving them magical new tools to outperform everyone else. It just means they're in demand because the market is vomiting money at tech companies, so tech companies are sucking up every developer resource they can find in their sprint for growth.
You can make developer bucks working as a blue collar worker on an oil rig, or as a normal dude on a fishing rig. These people aren't making cash because they're 'knowledge workers'. They're just supplying labour to a field with solid demand.
