Genes do play a role, but not such big of a role that you'll never be achive the arm size of what mreik has. It's like the same excuses overweight people make ( slow metabolism, can't stop eating etc ) where lifters who want to be in denial make up the excuse they don't have good genetics and dont take gear.
Thats all bull****, sure, people with better genes will be able to make progress faster and more efficiently but the average joe if determined can still make the progress the person with better genes did, it will just take more hard work and longer.
Of course anyone who is determined to bulk will get bigger
So your explicity saying everyone can get as big as an arm as meirk
And your implying that there is a set point, a certain size that all mankind can achieve, so there must be some information around that desrcibes the maximum size of the biceps that everyone can achieve.