I'm not so sure. At the moment it's a balancing act between range and weight. As battery tech improves it may end up as ice is now - they just fit a larger than needed fuel tank because there's little point in not having it and it can be useful from time to time.I doubt you'll get a 1000 mile EV... for the simple reason it isn't needed. 300 mile real world range, charging network as big as the petrol network is now, very fast chargers that can recharge 80% of your capacity in 15 minutes. Most carparks have charging points at all bays. Thats a far more likely scenario than 1000 mile range, and it addresses most peoples concerns / issues. Plus driving for more than 4 hours without a 15 minute break is just dangerous.
If you had a 500 mile ev and an extra 500 mile range was only going to add 50kg why would you not have it? Considering ice's can refuel far faster, refuel and availability would need to outstrip what's already available for ice just to make it even. Why bother if a massive battery doesn't take up much size/weight?
With the ice storage was always a minor issue - the development was in getting more efficiency from burning it. With the EV it already has the efficiency in use but needs development on storage.