This is a commonly misunderstood aspect of the math surrounding these types of things, thank you for explaining.

Another way to understand it if this is confusing which really helped me, is the way dodge scales in Diablo 3. Each point of dodge gives decreasing dodge% as you approach 100, but they're actually all equally valuable.

Let's say you have 10hp, and your opponent does 1 damage. The difference between 50% and 75%, and 75% and 87.5% is exactly the same in terms of tankiness, despite it seeming like one is giving you half the amount of evasion.

Assuming perfectly even luck and dodges come before hits for simplicity; 50% evasion means you can take 20 1 damage hits. (half miss) 75% evasion means you can take 40 1 damage hits (twice as tanky, three quarters will miss) 87.5% evasion means you can take 80 1 damage hits (twice as tanky as 75%, 7/8)

This continues all the way up to infinity at 100% evasion (where you could never be hit.) Someone with 99% evasion (only 11.5% more than 87.5) would need to take a staggering 1000 hits before dying (they are only hit once every 100 hits, and this is a disgusting 12.5x tankier than 87.5% evasion.)

Hopefully I didn't make it more confusing.