You are aware that some combos work even with proper DI, right? In fact, if a combo doesn't work with proper DI, it probably isn't going to be very usable in competitive circles. Note that substituting moves doesn't count as an escapable combo. In melee, Falcon dthrow to followup is a combo regardless of DI. DI only changes the nature of the followup.
Would you really like the chaingrab better if you could move all three sprites along the platform while you're being infinited. It'd feel the same to me.
That's not exactly true. They might become more situational, but to say that they wont be very usable is probably a bit too much.
And at least with combos that are inescapable, they only last for a few hits before DI plays a significant part.
There are also no such things as a zero-death inescapable combo in B+. All Zero-Deaths are pretty much worked for and earned on account of proper reading and tech skill.