I don't think you understand how bad his bat would play at the ML level now. He's never hit above .261 since high school. He hit .208 in a limited stint at Low-A last year, which for a college junior is laughably bad. He would probably hit .150 or worse at the ML level now.
Again, I think we're all just jaded by how bad our hitting prospects from AAA have fared upon being called up. Having Tucker, Santana, Singleton, Marisnick, White, Reed, and Teoscar all straddle Mendoza like she was a cheap w**** is NOT normal for a farm system. In fact, I'd say that it was a fatal indictment upon our hitting coach, the inability to get at least a few of our non-star prospects to translate their numbers from AAA to the majors. Regardless, there is no linear correlation here. The curve of suckitude tapers off, by the simple virtue of physics. When an athlete swings, some balls will have a decent velocity off the bat, and some of those balls will find holes. Take a .240 career minor league hitter in the A-system and weaker, and he's not going to go down to 0.150. .150 is for pitchers. Any NCAA athlete just putting their bat over the plate will get to that level. Jake Rogers WILL be able to give you a bat comparable to whatever defensive catcher you can throw <5M at off the street. And from the scouting reports, his defense should be even better than that of a FA.
Wishful thinking at best. There's no precedent or data on a below-average A ball hitter being called up, much less being called up and being tenable in any hitting role.
Not sure why the Astros are being singled out for young hitters not doing well. The success rate in baseball as a whole for prospects isn't very high. Regardless the Astros are not going to call up a catcher struggling to hit in the low minors to be their back up catcher; especially when Gattis isn't going to catch every day.