Yeah, big deal. It is really a PR or political announcement. Depending on the lay of the land between now and then they can reverse it or delay it at anytime. So big deal. If they said they were going to do it in 5 years would be a big deal. Not this.
But one thing might bite them. Some will look at this and say, "Why should I buy a ICE powered GM car or pickup if they might not support them later?" With the average age of cars in the US pushing 13 years, that's a valid concern. In fact, if I were buying a pickup truck or large SUV right now, it is probably enough to make me shop Ram or Ford and skip right over GM. And the benefit? They made some folks feel good who won't buy a GM product right now, anyway. So overall, I think its a dumb move that they didn't think through very well.
So I'm now imagining how we'll go from feeling great about ending coal mining and reducing fossil fuel production to opening up gaping holes in the earth to get the materials for these batteries. But we'll ignore that because it interferes with our green euphoria. (Nevermind the fact that natural gas is a fossil fuel and is required for the production of the electricity these cars will demand. Funny how some of the highly aroused green folk don't seem to get that.)