I disagree. The majority of our gaming group sleeves their cards. The choice is obvious.
Ha! The majority of MY gaming group doesn't sleeve their cards! LOL!
But, sadly, it doesn't matter what we say, it's always about the price point for games, the biggest bang for their buck is the bottom line, I'd be willing to bet at production meetings those folks don't even discuss making inserts that are big enough to hold sleeved cards.
An excellent solution would be to toss the insert (I do know many who do) and look up foam core inserts here on BGG and custom make your own insert, they are way better than most board game company's inserts, for sure.
+1 for D.I.Y.'s