Because Core 2 was a massive upgrade over AMD offerings
That is why.
I went all Intel starting with the Q6600 Core 2 Quad that I paid $273 for in 2007. My interest was video encoding and AMD products then were well behind what Intel offers and what AMD released later to compete against it fell well short.
As for your quote: I have an AMD Phenom, one of the early ones that nobody wanted to touch due to a FUD campaign. It's worked fine since like 2007. It outperforms the Core 2 Duo massively in the real world. While it is probably a lot slower than some of the more modern silicon I tend to ignore the benchmarks and just look at performance I notice.
Who today even uses a dual core processor? Even browsing (with video) now taxes quad cores.