So, assuming the same total number of vehicles is sold and used, then the mix of p% full EVs + (100 - p)% ICE vehicles can be better than the entirely hybrid fleet when

80 p + 250 (1 - p) < 180

170 p > 70

p > 7/17 ≈ 41%

So 1 EV and 1.5 ICE are roughly equal to 2.5 hybrids. And anything more is an improvement.