I'm all for an infrastructure that lets you create a chat group without selling your soul to a data-marketing demon or locking-in to a single source. IRC is pretty close, but the text-only nature is too retro for non-techies. It also keeps away the worst spammers and scammers, so it remains the best choice if the participants can cope.
But I don't think lack of development is what has allowed facebook to succeed. We've had people trying to lock in a community since the beginning - starting with AOL, even before the internet was a big thing for the public. Then geocities, yahoo etc .. they all tried to create a walled garden to make access simpler for their users : and lock them in. Facebook is only the latest and will likely fail too when people get as annoyed about having too many facebook messages as they have about email.
I can't believe the people who claim to use slack etc. because they're swamped with email. Once all their email tormentors find the new channel, they'll be there too.
What Laguna needs to do, along with making public IM easy for the masses, is ensure there is a scaleable method of filtering. That's what will keep a new protocol relevant.
Biting the hand that feeds IT
