I agree. It might depend on where you start the 'netbook' definition and how you count 'most'.

The EeePC was x86, the Chromebook Pixel was x86 along with many that followed with balance being ARM variants.

More recently you have convertibles/ultrabooks and their stripped down cousins (e.g. Microsoft Surface Pro vs. Surface 3/Go/Go 2 and Surface 2, Surface RT, and Surface Pro X the latter 3 being ARM).

Ultimately the netbook niche has been squeeze by ultrabooks and tablets to few offerings if anyone is even bothering to market computers that way anymore.