Yall are just wishcasting if you think someone who lost by 14 points is going to be able to convince GOP voters that he can beat Bob Casey who while overrated imo, is clearly stronger than generic D. He's not winning the primary again.
With that being said, Rs are going to have to find someone better than McCormick. He has no shot of actually winning this race
It can be difficult to understand as a Democrat but Republican primary voters have drastically different motivations and priorities than Democratic primary voters (a phenomenon that has only been exacerbated since 2016, though of course still existed beforehand). This of course doesn't mean Mastriano will win this primary if he runs, but if he loses it won't be because McCormick or some other person runs aggressively on electability. As I've been saying for months - the GOP's candidate quality problems are a systemic issue that can't and won't be solved in a single election cycle.