Why did Carmy never end up with Sydney?

Because Sydney is too smart to do something that stupid.

A) it ain’t over B) it’s employee/employer and that’s not cute, in principle C) it’s obvious - put the male and female leads together- therefore uninteresting

Because the show wasn’t written that way and they don’t appear to be interested in each other that way. At all.

They have so little romantic chemistry that it's actually impressive. They would hook up with Richie before they would each other.

I mean, if you want to see that, you can watch pretty much any sitcom since CHEERS.

Cause Sydney is going to end up with eyebrow kid