Where It All Goes Down
19th-Century England
Marx would be the first to say that his analysis is constrained by his historical time. He believed the economic mode of production you live under vastly influences your ideas and attitudes, so even if he thinks he's out-thought capitalism, he thinks he's still a product of it.
The biggest face of capitalism in Marx's day was the factory. Sure, he talks about gold mining in ancient Egypt (10.2.1) and about a bunch of other times and places, but the factory is still the chief symbol of capitalism in his head.
The brutal labor conditions of the Industrial Revolution inspired his anti-capitalism, but they also led him into a bit of a straitjacket as to how he viewed the system. "Capital asks no questions about the length of life of labour-power" (10.5.1), he asserts, when today Google heads boast about extending employees' lifespans (in the pursuit of profit, of course). Might want to add a few caveats to your rants, Karl.
Marx also centers most of his focus on England, where he, a displaced German, lived when he wrote the book. But he does include other countries in his analysis—like France and the United States in Chapter 10. Still, faraway peoples don't have all that much of a place in Marx's longwinded book.
All in all, Das Kapital is definitely a product of 19th century England (and Europe), challenging the dominant bourgeois economists who came before Marx out of the same geographic region.