So, those small groups who knew about it, they mined Bitcoin almost for free in large proportion.
Your forgot small detail here. Noone could expect Bitcoin will gain so huge price in so short time.
Because of that even pioneers who mined 10 000 bitcoins on their single home CPU spend their 10 000 bitcoin on pizza and were very happy about it that it worked. That their coins actually was worth ANYTHING.
You could develop it like this, to have most bitcoin first, but it could be easily worth nothing in time. Bitcoin turns out true technological revolution.
Actually those 2 pizza's was bought way later, if i am not wrong was in 2012, btc was 60 cents if i remember. by that time 12mil btc was mined, and frankly price can go even lower then that, if they sell. Maybe in future you won't buy even 2 pizza's with 15k bitcoins, believe me, the way was created bitcoin is a hard work from different expertise, they knew where the bitcoin will go, that's why i ask myself why they didn't make reward equal. There's no other justification other then, they wanted to get first 10 mil quick.