So, I've been doing a bunch of research and trying to find the answer to this question. Keyword searches have failed to find anyone discussing this topic, but I would imagine it has been discussed in the past. Looking to be pointed the right direction here.
After all 21M bitcoins have released to the public (miners), what incentive will miners have to continue the mining process?
There are already 21 million bitcoin in circulation and that means that there are actually 21 millions bitcoin that are released to the market and to the public to use. But I get what you are talking about you are referring to the maximum number of bitcoin to be mined and released to the public. If all bitcoin was released the miners will continue to mine and the incentive they will get is still the miners fee of course.