Whether ground combat is passe depends on whether you need to control an area. If you need to control it, you need boots on the ground. That means ground combat.
Denying someone access to an area is, of course, a lot easier: air supremacy and enough bombs will let you blow an area to smithereens and keep everyone out.
The US learned the hard way you absolutely need a good ground game in order to get anywhere. What screwed us in Iraq for so long was over-reliance on air power rather than fighting the insurgency down on the ground, face-to-face.
A ground war with Russia is pretty far out there in terms of likelihood, in any case.