Domestic runs are just easier without the headache of international. Also, I would hop from NY to SF, for example, grab dinner with a friend, and hop back on a red-eye, easy peasy.

While Europe is easy to get to from the east coast, there are a lot more fare consideration, Sat stay, min. Stay, etc. Yes, I know you can stitch a few different fares together. I go for a real vacation, rather than a MR when traveling international.

I have done 2 SIN-NYC nonstop hops (in 2019 and 2020, almost exactly 12 months apart, in January), adding the connection flight into SIN, those were a lot of flying, more than 24 hours.