the first season some teams had oldies, since they often where good. In the meantime the younger have trained their skills up while the olders where not capable of doing that in such a why, so the youngsters (which received training) are simply better nowadays...
I estimate the age will go slightly up from here because the ones that are young now but keep training will get better still, and it will take some time for the youngest to catch up on them, so they ones we have now will grow some years older before they will get replaced...
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