Why on Earth would anyone go with Beema? Its uses a lot more power and any competing solution and the BOM would be horrendous (would require an external ISP for the camera driving up costs and lowering the battery life and that is only one example).
Beema and Jaguar was great compared to any Atom Intel solution, they could have lowered the clocks and voltage and still end up faster(for Win 8 tablets) and Tegra was worse than the majority of the Snapdragons(for WinRT solutions), Snapdragons had proven hardware and software ecosystems, what went on between NV and MS is anyone's guess, but it was clear that Tegra was not a good choice at the time.
Same with Google taking on Denver, what went on between NV and Google for that to happen is anyone's guess, but even the 32bit TK1 kills it in almost all metrics, Google would of been better off just grabbing an off the shelf A57 solution. Denver is so bad that even NV ignored it for the X1, Denver is so bad that NV will(rumor) update the Shield and not use it.
When a company does not use it's own custom design for its own products, you question it. You should question it.
They took years to build it and they didn't think ahead for a 4 core and more cores version of it? Yeah right!