I'm not at all surprised by that which is why I honestly don't mind it's removal from campaign. Games are infinitely more complex than they have ever been. Player trends seem like they've drifted more and more in favor of online gameplay with every passing year. The only argument you could use for why split-screen deserves to stick around are players in rural areas and troops deployed overseas who can't get internet. You'd be absolutely right with gamers out in the country. You would also be right yet again with deployed troops if it weren't for them usually never hogging a console just for themselves with single player.
I don't think anyone, not even those who love split-screen cooperative play, would continued to be frustrated if they knew their campaign experience was being degraded as Mr. Griesemer suggests.