Forgive the title - unless a moderator edited it, in which case you don't necessarily have to forgive me 
Anyway - having worked with Flash, I've watched Pixi.js for a while. I personally like to think it's the way forward: I like its flexibility and the amount of features it supports. I also tried Phaser.io, but its outdated Pixi library was kind of a deal breaker for me (and what completely killed the project for me was that with v3 they broke compatibility completely, according to their FAQ).
Pixi.js on the other hand seems to try to keep their API intact, which are huge bonus points for me. When I first saw it, I ran into a few bugs, and since v4 was out for a while, I figured I'll just wait a little longer for v5 before committing to it long term. Though, seasons and years passed, and now it's 2018, but the last blog post is still from 2016 - there seems to be no news, at least not from the core developers. The "Blog" link from Pixi.js is outdated (though you can still get to it from Goodboy Digital). There's few committers, and the commits are spaced out quite a bit.
The lack of updates (and that I find very little about the company behind it, and their business model) worries me. I imagine you guys have a much better idea about what state Pixi is in. Are you worried? Are the lack of updates because it's just that stable now, or is it uncertain whether Pixi.js will even be supported longer than Flash? Is Pixi.js v5 just around the corner (I see an alpha tag on Github), or is it so far away that it's pointless to wait?