Dude are you serious?
How many of the people know difference between Marvel Studios and Content produced under license. FYI ABC and Marvel are acquired by Disney. So what happened to UTV Motion Pictures? They had it shut down just because they could not deal with Bollywood.
Fox Star Studios is doing good for itself. Star India is leading network in India. Hotstar is one of the largest streamer in India. What Else Disney wants? They need not add Disney prefix to everything they own for building its empire. They won't nullify what Disney Stands for by simply rebranding Star. If they want to do that they would have integrated every thing under Disney brand as I have mentioned earlier.
FYI before launching Disney+, they had to debate whether they can integrate Marvel and Star Wars under it for months. Also know that they had to transfer 3 series TO Hulu just because they are some what matured and not inline with what Disney+ stands for! They had to do that just for a series, you are talking rebranding Star.