Scott could be a much bigger part of the solution than he chooses to be.
For sure, I see him doing what you say, but I also see him regularly retweeting and responding to comments and questions from accounts with few followers, and particularly so from people from minorities within the developer community.
There are plenty of examples of people I can think of who behave in exactly the way you suggest, mainly spinning the flywheel of boosting the online presence of already famous people and not engaging much with outsiders, but Scott not only isn't one of them but perhaps one of the best examples I can think of of actively doing the opposite of that.
onion2k I ask you to look again at his Twitter stream and podcast, and re-assess your evaluation of him.
This is not a problem that needs to be solved, it's just something to be aware of.
Usually they control the conference circuit by donations and are able to de-platform people who would tell the truth.
It always pays off to look at the git history, which few people do.
You should listen to Scott's podcast: he has a wide array of guests, in many diverse topics (even topics that could be seen at odds with his employer, Microsoft). Most of them are people I've never heard of. If there are gatekeepers, Scott isn't one of them.
It's not his job/role to give people breaks. He's not a Hollywood impresario, he's a blogger. If people are good, they will be discovered.