You have explained your rationale for why legendary prestige is so hard to achieve. Thats one thing, and however you want to define that is your call. But the description and/or math is another thing. The description for legendary prestige says must have worthy prestige AND have traveled more that all of your distance traveled after previous prestiges. I traveled roughly 101000 before my first prestige. Game says I need 10x that to get legendary prestige. Its off.
 "Fish Legend Fish"){kind=icon}
 "Light Speed Runner"){kind=icon}
 "SuicIDLE"){kind=icon}
lol usually people point out the shrimp being out of place, I'm happy to see the minnows getting scrutinized finally :)