No fair point. But once a team in the group stage can't qualify, that's that. They aren't playing to avoid relegation or anything. And with massive groups it'll be a long stretch of games - it's not like the current format where the only dead rubbers occur in the last round or two at worst.
Given the top 5 places in each group of 10 result in some sort of potential to progress, you'd need to seriously stuff the first set of games to be out of touch for a long stretch of games. There is certainly potential for the worse off teams to end up playing 3 or 4 relatively pointless 'group stage' games though, I agree.