Curse of sequels
Money.
That's always the root of all curses, although the root of all evil seems to be 'lust for money' or some such thing.
In any case, they should never have made a sequel.
I don't mind Cobra Kai, although the teen drama gets silly and tedious quickly, because it's more about 'aftermath in the real world' than what the first movie is all about.
From my viewpoint, the first movie seems to be more of a philosophical thought than 'realistic depiction' of anything. It is more of a case of bringing the world of Zen koans and eastern, spiritual-based wisdom to western audiences (albeit diluted and in a ridiculous form).
The first movie is more of a philosophy between internal and external, what Karate really is, learning from life even during difficult circumstances, internalizing spiritual insights that can then be channeled to creativity like cultivating Bonsai trees and utilizing Karate to save your life.
The 'romance crap' and the 'dramatic conflict' stuff was just added there to make it more 'cinematic' and movielike, to draw in western audiences, to give them what they expect.
But somewhere inside the movie, the deeper message is still intact, and the movie clumsily brings it through (although some people rather focus on the external 'realism' type stuff, like 'can you really learn Karate from waxing' or 'can you really become good in Karate in such a short time' and 'why doesn't Daniel do weight training and jogging' and such) to the viewer.
Because the first movie's story only acts as a container to fill with the spiritual message, and to push western, superficial people a bit towards enlightenment, a sequel is a silly and doomed idea.
Of course the moneybags want more money, so if a movie, even a 'Zen koan in movie form' becomes successful, the moneybags want to make a sequel.
How do you make a sequel to movie, whose focal point is 'internal wisdom', and not 'what silly things happen to a goofy character'?
The movie is called 'Karate Kid', because eastern wisdom called 'Karate' is installed deep inside the 'Kid'. It's not about 'Kid doing Karate moves' or 'Kid having Karate fights'.
It's not about the external Karate. It's about the internal Karate - something that exists as living wisdom in the Kid's everyday life.
To make a sequel to something like this, is an idea exactly as stupid as this sequel shows it to be. Now it's no longer about the mystical, elusive wisdom and eventually, Zen.
Now it's about 'Miyagi's and Daniel's Goofy Adventures' and then of course more drama and romance crap for everyone. Sigh.
It's like they forgot completely what the first movie was all about, and decided to make as predictable and stupid movie as possible, all the while not even having Karate in the movie, internally or externally. The wisdom doesn't exist anymore, because drama, romance and the typical bully stuff must form a 'safe story' (=cliché-ridden, soulless formula).
This is the curse that happens to any successful movie that has a soul and originality.
Look at any great movie that then suddenly became a 'franchise'.
Back to the Future - good movie, but the sequels just became a parody of themselves. Having Doc say 'This is heavy' and Marty say 'Great Scott' completely destroys any quality and logic the movies might have otherwise had, and shows exactly what happens when people make sequels regardless of if the movie actually NEEDS a sequel or not.
The Terminator (1984) was a perfect story with perfect Bootstrap Paradox, and then they had to ruin it with 'repeat the story without the gore and with some annoying kid ruining everything, plus tear the perfectly done timeline explanation to little pieces and now nothing makes sense' crap.
I don't get why people like that particular sequel, the first movie is atmospheric and intense (and unique), the sequel is a pale copy at best.