Lol this is just stupid. Virtually every keeper can bat, no they have to bat. I am genuinely struggling with your train of logic here lol.
Because you don't want to.
You're focusing on expectations rather than output.
You're being deliberately obtuse.
Because every keeper can bat, doesn't make his contribution as a no. 7 any less viable than Kapil's.
If both are batting at 7, how is Kapil's contribution greater than that of Healy's?
But to you, one makes Healy non viable, despite he's one of the greatest keepers ever and Dev, despite being just good at his job, it makes him an ATG?
You're focusing on one not generally having that extra value, but it still the same added value that the other guy provides, that you say isn't good enough.
You are basically saying, both batted at 7, but was want good enough, while the other was.
This isn't Imran who's an ATG bowler who on bowling skill alone can walk into most teams in history and who's batting would then be an added bonus. Plus is a candidate for an AT world XI, and lock for a 2nd team. You aren't getting great bowling from Kapil.