Miners don't sell all 3600 coins. I don't sell the coins I mine (never have), along with many many many other miners.
Then, besides being a miner, you are also one of those "new investors". You are efectively buying your own coins.
I.e. you have been financially supporting the bitcoin system with
your own money. The day when you will finally decide to get your due payment, whether in dollars or in lamborghinis, you will have to get it from other new investors -- who will have to buy all the coins that your collagues will issue that day, and
also buy your coins for whatever price you expect to get from them.