Solved! Why "switchable graphics" is not available for Hi-End gaming laptop?

[lgmcben]

After a day of googling, the strongest switchable graphics gaming laptops I found is the ones with Radeon HD 5730.

For example,
- Lenovo Y560
- MSI GE600


Why can't these arrandale-based switchable graphics laptop use something like HD 5870 or GTX 280m?

I assume there's a good reason behind it?

Thank you in advance!

 

[Maziar]

There are laptops the can handle GTX 285M/HD 5870M but they are significantly more expensive than those MSI/Lenovo models