Well, it's simple math: if you write ten wonderful posts every day, and ALL of them receive ten merits, you will need only 400 years to achieve 15 millions merits. Well... good luck! :-)
15 million merits is not possible in one lifetime now. Regarding posting quality, I cannot comment about all members but have seen some exceptional posts be new members. Merit system is a good motivation for everyone here.
I wonder who the first one to 15 million merits will be 
I like this change a lot
. Hopefully we'll see an increase in post quality 
I like this change a lot
. Hopefully we'll see an increase in post quality 15 million merits is not possible in one lifetime now. Regarding posting quality, I cannot comment about all members but have seen some exceptional posts be new members. Merit system is a good motivation for everyone here.