why dont many people pan sear short ribs?

You can’t cook the big bone-in pieces well that way, but you can get boneless and cut slices or get the thinner sliced bone in cuts and sear them. That’s what Korean kalbi is and it’s delicious!

Not my picture. I wish it was!

Yes the connective tissues in ribs is tough and you have to break them down so slow roasting in oven or in a slow cooker or pressure cooker is the way to go.

Sear them as a last step .

When I buy short ribs I always braise them (which means cooking them in liquid), but I always sear them in a cast iron pan first.  You will want to do the same.  My default recipe is an Asian-style recipe that is super-easy and the finished product literally falls off the bone.