I agree. BM has potential. I just don't think he beats out JG or HB.
Hill is not good. JT is a turnover waiting to happen.
I'm going to make a serious response though I'm pretty sure of your motive here....
BM does have potential. We have no idea what HB has so it is pretty foolish to say that BM won't beat him out or that HB won't beat them all out. We just have zero to go off of at this point concerning HB.
BM played like a Freshman in trash time vs UTC and UF. He played well before being knocked out of UGA, MSU, and Bama. Most of that was due to "moxie"... or swagger or confidence or whatever else you want to call it. He went out and decisively made plays. There were mistakes but those can be coached up. He wasn't the same vs UK. He was tentative. He made bad decisions rather than playing fast and instinctive.
So...
You have JG who may well have hit his ceiling. Even if consistent, he appears to limit UT's O and especially vs the top tier teams (He STILL hasn't led UT to more than 30 points against any FBS opponent).
You have BM who appears to have a higher ceiling but has to regain his confidence AND catch JG to a significant degree in his understanding and management of the O. BM also may be susceptible to concussions.
You have HB who best case comes in and has to play serious catch up. I've watched his highlights and while he has a nice arm... it would be no better than 4th in the QB room we're talking about based on those highlights.
You have Hill who I personally just don't see being a real threat. He was not greatly successful vs much weaker competition at Maryland.... and isn't a very accurate passer.
And you have Shrout who may have the biggest arm in the group but even midway through his 2nd season appeared to have less of a grasp of the O than Maurer as a true Fr.
On the flip side... you have 5 talented guys and any of the 5 could step forward (even JG could surprise me again) and become the QB that leads UT out of the wilderness with some big wins next fall.
Realistically, Pruitt seems to dislike unknowns. JG is a known quantity. BM is to a lesser degree. I would be shocked to see anything other than them as #1 and #2 come the end of August '20.