That is logical.
DAWs from companies with own controllers do not want to risk loosing hardware sales.
Cakewalk had no devices, so opened API. Updated it when Roland V was obsolete.
Presonus and Steinberg have own devices.
Tracktion and Bitwig cooperate with particular producers, so no API.
Cockos has no devices, so it has API. Mixcraft could probably benefit from that, but they do not want.