I honestly don't have any strong opinions on this either way... but I imagine the examples you gave of excellent cricketers were maybe one in a million... how many average cricketers in their day were hurt and seriously injured? How many amazing cricketers did we never see because they got too injured to play the game at the elite level? We'll never know because there aren't any statistics on this... but honestly, I don't think someone's life should changed dramatically through injury because they enjoy a sport. The examples you gave are incredible athletes... but the protection isn't for them, it's for all the people that don't have those incredible reflexes. I can't imagine that padding slows down reflexes, it just allows people to play without ruining their life.
I just think it hampers sportsmen from reaching what they could achieve. By putting a helmet on a 10 year old kid you are already sending the wrong message. Maybe at 16 years it could be a decision he/she makes for themselves. Honestly hockey is way more dangerous than cricket and they don't run around in helmets, but in 10 years time I can see it happening.