Thinking about battery capacity improvement, I took a look at what happened with 21700-type batteries (as used in the Varg). Following examples are from leading supplier Molicel with their release year, capacity and energy density.
2021: P42B 4.2 Ah, 226 Wh/kg
2023: P45B 4.5, 242 Wh/kg
2024 P50B 5.0 Ah, 260 Wh/kg
2025: P60B 6.0 Ah (energy density not officially announced, likely at least 290 Wh/kg)
Max discharge rate (think max power available) and max charge rate (shorter charging times) keep increasing as well.
For instance P60B can be fully charged at 5 C in 13 min
Here is what the Varg battery capacity is (or would be) with 400 of these various cells:
2021 P42B: 6.0 kWh (used in 2022 Varg prototype)
2023 P45B: 6.5 kWh (used in 2023 Varg MX)
2024 P50B: 7.2 kWh (similar cells used in 2025 Varg EX and MX 1.2 from unspecified supplier)
2025 P60B: 8.6 kWh (not yet in production)
That's 43% capacity increase in 4 years, about 10% per year.
That's no pie in the sky solid state batteries everyone is pouring millions in that may or may not become a commercial reality in the next 10 years, that's actual improvement with current technology.
TLDR: current trend suggests doubling battery capacity (therefore range) about every 10 years.