@LightRays,
Neither method of handling a group is right or wrong. I'm sure the people your wife focuses on (at least for a time) feel very special. And the people you talk with like the dynamics. Different strokes.
Why does this bother you so much? Is it that you want to leave earlier? If that's the case, then set a hard end time, add it as a calendar reminder on both phones, and that's when her ride is leaving.
If you want her to pay more attention to you at these parties, I think you need to suck it up and get over it. You have plenty of her time and attention at home. Let someone else have a share.
If you want her to meet more people during these social situations, recognize that she probably won't do so. A reasonable compromise is to introduce her around to everyone but then, once she gets her laser focus, let her. You can also rectify this by giving her other situations to meet these other people, say at a dinner. It's hard to ignore the two other people at dinner when there are four of you sitting close at a restaurant table.
Is it that you run out of things to say to all of these other people, and want to be socially rescued? Then, like I said, set the timer and have a built-in excuse. "Sorry, but it'll be an early night for us tonight. I'm looking to start a new exercise regimen and I like to jog early in the mornings." Or don't even offer an excuse. You don't have to. Just say
thank you for the lovely time, it's got to be an early night for us, and then go. They won't send the party police after you if you leave early.
If you and your wife are hosting these gatherings, then host them out at a restaurant or the like, and you won't be stuck with the serving and cleanup.