I don't see this one as necessarily true. And it doesn't even seem to hold up in the one example you gave of Vue. Looking over the patreon page, Evan seems to be totally marketing the technology and not marketing "himself" at all.
One might say that other open-source projects don't make a significant income because they don't have value, but I think you only need to look at e.g. the npm download stats for many packages to see that this isn't true.
Put another way, _many_ software libraries enable huge amounts of business value that is not captured by the authors of those libraries.
For instance, if you're a JS dev, you've probably used lodash or moment, but maybe can't even name who the authors are of those projects.
This idea of "hustle as your new second job" is a better phrasing than my parent comment where it sounds like I'm implying that self-promotion is bad or somehow empty.
Becoming a personality is an excellent strategy - if you're known and loved you'll never starve.
I'm mostly trying to point out that time spent hustling takes away from time building. It's still valuable in it's own way, but many OSS devs (who have created software people find valuable and use) don't want to travel to speak at conferences to pay their bills.