Convenience Stores in the US should have dine-in areas if they serve hot foods

It’s likely a cultural thing.

For instance all the countries you mentioned with space to eat in are also countries that have universal healthcare. So perhaps, in those other cultures, there is greater empathy for fellow persons and value in service to and hospitality for others.

The food there is also much better than the food sold in convenience stores here. I also think it's a model here where the idea is to get as many people in and out as fast as possible, no lingering.

It must be regional, most of the 7/11's in the part of Texas I live in do have tables, chairs, and a long bar with stools against the window. They're almost always empty though except for around lunch time. But they're not regular 7/11's I guess, they all have a little taqueria called Laredo Tacos built in to them. Some Valero stations and independent stations have them too though they don't all have taquerias.

Tables!?!?!?

That's valuable floor space that could be used for more product. Tables don't make money.

Welcome to the US

Having people sit around and make a mess while clogging limited parking just makes more work and can potentially reduce sales. Also, seating vs non-seating changes the health standards required in some places.

Most of the newer Sheetz that have been popping up near me have those metal picnic tables outside.

"even fucking Mexico"...

No one should be eating 7-11 "food".

Let's not make it more likely to happen.

That such things exist is the problem, not where to eat it.