Has fundamentally changed.
Once upon a time they were a great game developer who made exceptional games with a great story, and tied in well with the community to really expand that.
With Steam being the 800lb gorilla in terms of online distribution, now getting a lot of competition from others ala Origin, UPlay, GMG, etc, they have doubled down and basically made Steam the most important piece of software in their portfolio. Sorry folks, don't think we will see Half Life 3 any time soon.
Their business model has changed as well. They went from selling copies of games to becoming a distribution network and "item shop" with the skins they sell in games like CSGO/DOTA. CSGO has not received any real changes despite the game being in dire need of them (browse HLTV or Reddit for any evidence), at the development level. Valve employees are allowed to choose which products to work on, and since DOTA is a cash cow the most effort is spent on that, and on Steam itself.
Don't get me wrong -- I really love Steam. I'm the proud owner of 300+ games which I mostly don't play :) However the idea that Steam is an amazing platform is just ridiculous. It has poor support for most everything, it's poorly designed, the social features are atrocious, etc etc. But it provides a stable base for a delivery platform, and that has been its strength, and also the reason Valve has succeeded. I am glad that Steam look at Twitch as a competitor, but making it so that their streaming is only accessible through the Steam client is well -- a terrible decision. The social features that exist within Steam are subpar at best, so the benefit of the integration is lost on me. Twitch offers a lot more, and with the API they have there are a lot of neat tools that people have already made to take advantage of it in a larger way.
Honestly, I hope Steam's streaming platform falls flat on its face; perhaps it will enlighten them that competition is going to be there, and they should get back to the things that make them great -- making great games, staying engaged with the community (which has fallen off considerably in the last few years), and developing Steam to be a much more premiere community rather than a game library.