Hey old man (I'm 40 so for those 2 extra years I can call you that ;)).
I have a very similar situation, with a 10, 8, 5 and 0 year old (yeah I'm a bit more crazy than you). Difference is that I actually do have a bit of spare time.
I also fondly remember all the half-life games, as memory permits of course.
For me this is a different story: The whole VR experience passed me by a bit, until now. By seeing this, my hands are itching to pull out my wallet and pay a crazy amount of money for this toy. The benefit of 40 year olds is that they probably can cough up the money for all this VR stuff.
I'm not sure yet, but there is definitely a strong itch now that I see this.
A new HL game probably also means some cool multiplayer games are coming up. I'm not only thinking about Counter Strike, but also Team Fortress.