I can understand Austin's sentiments considering how he himself spent years upon years in the wilderness being stuck with less than convincing gimmicks and feuds before finding his groove with the Stone Cold gimmick, but some of these statements seem a bit of an overreaction to me.
As someone who saw A.J Styles perform for the first time at this year's Royal Rumble, I think he has been pushed and protected way beyond what was warranted with the overall skills he has presented as a sports entertainer thus far. He comes in and straight-away defeats a future HOF'er in Jericho, gets put in a program with The Miz who I believe cut the promo of the year thus far just one week into Styles' tenure, not for his own benefit but to sell AJ Styles' story and lend a bit of legitimacy to Styles amongst the vast WWE demographic that hadn't seen him before the WWE :
Destroys Miz despite Miz doing almost the entirety of the work while building up each and every match from scratch with his incredible mic work while Styles hardly spoke and was limited to being a bell to bell performer with a very less defined character to boot. After destroying Miz, he immediately enters into the feud with Jericho who again carries the entire mantel of building up each and every match and showing his versatility while playing a face, tweener and heel all in the same feud ! Styles, to his credit plays his part in the ring being a part of some great matches like the Tag match with The New Day but still far from convincing as an overall sports entertainer. The series ends at 3-2 in Styles' favour with Styles immediately getting into the title picture within 3 months of his debut.
In the title feud, he technically beats Reigns not once but twice in the same match, an occurrence unheard of with Reigns and ends the title feud coming out with much much more legitimacy, exposure and stardom then what he entered with, despite losing both the matches he at least develops some character, has more exposure on the mic and plays a leader to a faction. All in all, his booking in the feud helps him take a big leap as far as all round skills go... and straight after he enters into the feud with the face of the company himself. Sounds like close to perfect booking for a performer who is 5' 10'' 218 lbs, good-great wrestling skills but weak on the mic and having a less than defined character and less than optimal charisma. Have to disagree entirely with Austin here, Styles has much more to prove before being a permanent fixture in the main event scene, at least for the WWE viewers who didn't know him before his signing.