Scared them off? Is there any documentation of that? My understanding is that the split was amicable. SkyTalks has immunocompromised people on staff and they chose to voluntarily leave defcon because they wanted to continue masking mandates while Defcon did not. Bsides welcomed them with support in their conference(helping with Token Drops and scheduling) and Skytalks occupies a space that is physically separated from Bsides(as in a different hotel on its top floor).

SkyTalks are as awesome as they always were, I'd argue its even better since now you dont have to sacrifice other things at defcon to see skytalks. You can now have dedicated time for skytalks.