" It's an open secret that ARM was (and still is) selling the CPU design at a discount if you integrated their Mali (GPU)."

Why is that bad? Not only it's common business practice (the more you buy from us, the cheaper we sell), it also makes sense from the support perspective. Support the integration between their cores and a different GPU would be more work for them than integration of their cores with their own GPUs.

That's why companies expand to adjacent markets: efficiency.

A completely different thing would be to say: "if you want our latest AXX core, you have to buy our latest Mali GPU". That's bundling, and that's illegal.