You can actually see the progress made in the pivotaltracker, but I doubt you'd know what to make of it https://www.pivotaltracker.com/n/projects/2124891
Mainnet release candidate is set for the end of July, and you can watch the team progressing with each task along the way. That will basically be a ready mainnet, though it will probably undergo some auditing and probably public testing. Nobody wants an EOS like code being pushed into use with huge issues in it.
In the end there's no aeternity without the community but I think that we're not yet at a point where we can expect too many developers to come onboard because we still owe them some tools to be able to work with our blockchain.
We have some plans to engage more developers but I'm not sure if I can talk about them just yet.
The most important thing everyone can do is to foster an open, welcoming and healthy community. (I'm a fan of the Rust Code of Conduct)
There will be no mainnet launch on june 21. Look at https://www.pivotaltracker.com/n/projects/2124891 It is mainnet release candidate, not mainnet launch. It means that it will start getting tested and there will be a lot of bugs that will need to be addressed + they are late on development schedule with 1.5 month or so.