I don't need new selectors, I need a way to specify layouts. You know, to do the same things as tables did back in the days, but without all the ugliness.
The reality is that there's no such thing as CSS4, and no such thing as CSS3 either: starting with CSS3 the spec was "modularized", meaning it was broken up in a bunch of separate and mostly-independent "modules", which are grouped in a "level" but are specified on their own[0].
So the situation is that TFA talks not about CSS4 but about "Level 4 Selectors" (a draft), talking about "CSS4" is language abuse. The specs I linked are Level 3 specs, but independent of selectors and of one another (columns are a CR, grid is a working draft).
To sum up, your question does not really make sense. Grids and columns are part of "CSS4" insofar as they are part of "CSS3" through being Level 3 specifications, but that's completely meaningless. Level 4 selectors could become recommandations before (level 3) grids reach that state, or not. There's no dependency. (columns are already supported by all modern browsers except MSIE).
I'd recommend using (and abusing) http://caniuse.com/ to see the implementation state of each spec, it's become especially important with modular level 3 specs as implementors are free to add one level 3 spec and ignore an other.
[0] You can see a list of specs at http://www.w3.org/TR/#tr_CSS, note how some Level 3 specs are Recommendations, others are Candidate Recommandations, yet others are Last Calls or Drafts.
In summary: no, they're in CSS3; but it's all modular and might not be implemented at the same time.
There is incentive for MS Grids to go forward soon, they're important to MS for use in Windows 8.
Also, they're cool, or rather they're a sane layout scheme and it's awful that CSS hasn't had one up to now.
The irony is that Firefox and Chrome will implement them at about the same time that they become official. But we won't be able to use them widely until IE7,8 and 9 have faded from the web. MS giveth, MS taketh away.
One problem with that idea is that tools like CSS tables still have some dependency on the source order in the HTML. So do certain other popular tools, notably various aspects of float positioning.
If we're going to have a proper separation of content from presentation, such that we can do things like alternative layouts for responsive design or A/B testing using only the presentation layer, there has to be a viable mechanism for overriding that sort of source-order dependency.
