Hindsight is 20/20 but in retrospect, it would likely have been easier if I-70 had followed the route of US 285 and 50 over Monarch Pass to Montrose and then up to Grand Junction from the beginning. Glenwood Canyon is certainly an engineering marvel but it's always been "high maintenance" and always will be. And realistically speaking, I don't think there's a viable alternative that is anywhere reasonably close to the Glenwood corridor.
So my guess is that they'll do what they can to patch Glenwood Canyon and like the wildfires that ravage the mountains every year, periodic Glenwood Canyon closures are just going to be something we have to live with.
"Way back when" it might have been possible to build a new route that roughly follows Cottonwood Pass, heading South from Gypsum, crosses Gypsum Creek and then goes over the relatively flat ground (at least compared to the areas North of Glenwood Canyon, which is extremely mountainous) and approach Glenwood Springs from the Southeast:
But starting a project like that from scratch now would be ruinously expensive and while patching Glenwood Canyon until the next big mud slide pretty much "kicks the can down the road", in practical and political terms, it's the most reasonable course of action.