Techcrunch has basically been an ad network for companies who want to promote themselves. Other open source projects probably don’t have a budget to pay for an a̶r̶t̶i̶c̶l̶e̶ ad spot.
Mastodon.social just went over the 2 million user mark. The switch to fediverse and fediverse adjacent is going pretty quick.
I’ve been on Mastodon for over a year and the content simply isn’t there. Several of the people that I follow on Twitter have tried moving or duplicating to Mastodon. They’ve had a fraction of the visibility and engagement from commenters that they would get on Twitter. Invariably after a few months they have essentially given up on it as a primary medium. For me the discoverability is essentially non-existent, which I don’t think is helped by the idea of it being based around instance-local communities, which have no meaning when you’re looking at something like Twitter.