There are pure physical limitations to charging time and storage capacity per unit size that we're not going to break through, unless/until some truly revolutionary battery/storage technology emerges as viable within the market.
Charging rate (as we discussed early in this thread) is non-linear, with charging being faster when the batteries have less charge and slowing as you approach 100%. We think in terms of gas tanks where there'd never be a reason to stop before it's "full", but that won't be the paradigm IMHO when road tripping with an EV.
Charging rate is also dependent on the type of charger. A Level 2 charger (that you might put in your garage for overnight charging) is WAY too slow for road trip use. But a 250 kW or 350 kW (current max) charger will add charge MUCH faster.
What I think that Tesla has shown is that with planned charging and Superchargers, you might go from 10% to 80% in 20-30 minutes which is plenty to get you a few hundred miles of range. A few hundred miles gets you to the next charging station where you may want to get out and take care of food and/or bio breaks anyway.
Who has all the raw materials for these batteries?
My limited understanding is that the US has an untapped reserve, but we're not going to go find it. Is this true?
Depends on which materials you are looking for. Apparently lithium is plentiful. Although I don't know how much actual mining capacity we have worldwide to meet a major spike in lithium demand. It doesn't matter how much there is if we don't have an industry that's sized to dig it out of the ground at the rates we need.
The bigger issue is some of the other metals like cobalt and nickel. That's why automakers are trying to work with the LFP (lithium iron phosphate) chemistry to take some of those more rare metals out of the product, but unfortunately it's currently at lower storage density relative to lithium ion, but at lower price too.
The industry is searching for a way to recycle batteries, but it remains to be seen if that can be done effectively and economically.