Could it? No not every time. I won't say it is never offered but it is rare and comes with its own set of problems which is why it is not often used.
If I buy the domain at abc.com registrar and you own the abc.com registrar and your company is an Afternic Partner and agree to sell the domain names coming from Afternic on your company's website as part of the network and you give up real estate on your company's website to showcase this Afternic listing I placed for sale, how would you feel if:
Instead of Afternic giving the domain to your customer at your company abc.com a service agent from Afternic contacted me and said, Hey, we know you use abc.com but there is this other company over here, xyz.com and they also sell domains and that is where the domain you bought is located. So we are going to have you create an account at this other company and then give you the domain there. And boy am I happy because I never heard of xyz.com before but they have better pricing or a control panel I like better, or I just got my first domain to start a business and now i buy all the extras like email and hosting at xyz.com instead of abc.com your company?
I know how you'll feel. You'll be mad and think what are they doing taking my customers away after I made the sale for them?
On the other hand the service agent may call me and say try xyz.com because you can get the domain 60 days faster there. I may not like that. I may start thinking this is a scam, I never heard of Afternic or xyz.com I bought my domain at abc.com. Or about a dozen other negative scenarios I can think of off the top of my head. Heck I may not even answer your email or phone call at all because I expected when I bought the domain I wanted to just get it not learn all about how 60 day locks and transfers work.
So really the best situation is to list domains on the network that can be transferred.