After order 66 in Star Wars the transfer of the clones went from the Jedi to the Sith and yet in Ep7, Phasma states that Finn came from a family, so he is obviously not a clone. Were the clones phased out later on? How did that transition work?
Clone Troopers were expensive and died relatively young. The technology used to create and mature them rapidly led to degenerative genetic disease. The Clone Wars and Rebels cartoon show these clones dying off.
At the end of episode 3 and between the 20 years to Episode 4 A new hope, the Empire started replacing clones with recruited and trained individual citizens of the Empire. By A new hope, they are regular people, Storm Troopers. Luke was considering enlisting. It's cheaper to train people to be glorified police then it was to constantly replace military grade clones. Clone Troopers were there to win a war, Storm Troopers keep filth in line.
By Force Awakens Storm Troopers, the military foot soldiers of the Empire don't exist. Instead we see First Order Troopers, which are mainly kidnapped children brainwashed into becoming thoughtless killing machines. This was 20 Years after Return it the Jedi. The First Order has a fraction of the influence and resources of the Empire, which fractured into multiple groups and had to resort to stealing babies out of some desperate attempt to stay in power.