Is there any specific reason why consumer grade router companies (like D-Link) drop their own OS entirely and shift to a open-source alternative? That should br

Is there any specific reason why consumer grade router companies (like D-Link) drop their own OS entirely and shift to a open-source alternative? That should bring down development costs somewhat I'm guessing and force them to make different boards compatible. Not a hardware guy, but I've looked at D-Link firmware code in the past, and it is just utterly shoddy. Just making the hardware and making sure it is compatible with some router-os should be simpler. (Essentially what happens in the mobile/laptop industry with android/windows).