In new episodes of Star Wars (specifically Ep.II Attack of the Clones) there were clones that was created from Jango Fett, including Boba Fett, so does it mean that in the original episodes (IV to VI) all Storm Troopers are the same clones, and they all look like Boba Fett?
No, the original clone army consisted of clones of Jango Fett, but as the Stormtrooper Corps was built from that original, clones of different people and even just normal born humans were allowed to join the Corps.
For more information see the Star Wars Wiki.
Star Wars: The Bad Batch establishes that the Storm Troopers were decommissioned shortly after the events of Episode III, and replaced with conscripted Storm Troopers (rather than the Storm Troopers just being Clone Troopers under a different name). There were several reasons behind this:
- They had served their purpose (i.e. the manufactured war that allowed Palpatine to establish the Empire in the first place) and were no longer needed
- Hiring conscripts was cheaper than paying the Kaminoans to keep producing more clones
- There are an increasing number of instances of clones disobeying their programming
- Simple racism, with many Imperials looking down on the clones as inherently inferior
In addition, Star Wars: Rebels demonstrates that the regular clones' accelerated aging would have made them too physically old for active duty by the time of the original trilogy, so they likely would have all retired by then anyway, even without the reasons listed above.