George Lucas chose to film and release the Star Wars franchise in a strange way, and that created a big problem for the Jedi in each trilogy. By starting with the original trilogy in 1977, Lucas first introduced the concept of the mystical power of the Force to audiences. While Luke Skywalker doesn’t utilize his powers much in A New Hope, he begins to train and hone his skill in The Empire Strikes Back. By the time of Return of the Jedi, Luke is considered a Jedi Knight. But even at this level, his abilities seem to pale in comparison to the average Jedi from the prequel trilogy.
Aside from Luke Skywalker, Obi-Wan Kenobi is also weak in the original trilogy compared to himself in the prequels. While this may have been due to a combination of Obi-Wan being 57 and his skills being out of practice, it still seems like there’s a large difference in power between the Jedi in each trilogy. The Obi-Wan Kenobi series tried to explain why he’d become so weak by having Vader drag him through a burning fire, but his skills later returned. While the Star Wars franchise introduced an explanation for why the Jedi in the original trilogy are so much weaker, Disney has complicated things by ignoring it.