I would say the most likely reason is because it would take great deal of time, energy and money and would distract DxO from doing what they do best.
There is a saying “Jack of all trades and master of none”, which is usually what you get with software that tries to do everything.
DxO PhotoLab is (IMO) the best RAW image editor around - one of the reasons is that they also provide lens profiles to get the most out of your equipment.
If you want to do tethered shooting, use Capture One - it is very good for tethered shooting but not so hot at image editing.
I open PhotoLab and point it to the folder that receives the shots from Capture One. As the shots arrive, PhotoLab updates and, if you want, you can edit the images straightaway.