There is a bunch of, relatively speaking, inexpensive EVs with 200-250 mile (320-400 kM) range -- e.g., the Kia Niro, Subaru Solterra, Volvo C40, and late model Nissan Leafs. All, in my experience have enough range for day-to-day use (40 mile daily commute, 80 miles airport runs) without "range anxiety", they even work well enough for weekend trips out towards the limit of their range with overnight charging on a level 2 charger.
Where they fall short for my use cases is for road trips in the 600-800 mile range where you're going to need two or three charges -- at least for the two we've settled on (the Niro and Solterra) which have relatively low acceptance rates (77 kW for the Niro and 100 kW for the Solterra) which means that those trips involve three or four hours of charging time (especially in the winter).
So this got me wondering, some of Tesla's Superchargers are capable of 250 or even 350 kW (presumably because some models can accept a charge at these kind of rates) adding 200ish miles of range in around 15 minutes (going between a 20 and 80 percent charge) so it seems that if a Niro could accept a charge at a similar rate five to 10 minutes of charging would add a significant amount of range. This would (for me at least) completely change the experience of a road trip in one of these cars -- and would seem to make for a very nice range vs. charge time vs. battery cost in "moderate priced" EVs.
What determines/limits the DC charging rate of EVs? Are there significant hardware costs that increase as you support higher charging rates -- therefore undercutting the cost savings that come from smaller battery packs?