Problem is John Carpenter never meant for Myers to *be* the franchise. His original intent was for it to be like Creepshow or The Twilight Zone, an anthology series of different stories. The only reason Halloween 2 happened the way it did was because the demand for an extension of the story was so high that Carpenter had no choice but to.
Halloween II(1981) was going to have the be made, Carpenter left a cliffhanger at the end of the first, and anything other than a direct sequel was going to be panned.
Halloween II ended up being successful and the most mainstream Myers movie(every casual from the 70s/80s considers Laurie Myers sister, only a niche fanatic base hates it for some reason) and many consider it better than the original.
Halloween and Halloween II were perfect movies and did the job of scaring the audience while getting them to root for the hero’s in Dr. Loomis and Laurie Strode while telling a detailed and tragic story of a sociopathic escaped mental patient going after his sister and other victims.
The problem is with Halloween 3, people would’ve accepted Halloween II as the conclusion of the Myers story had 3 been a really good story, instead they went with the movie they did and it was niche.
They had to introduce a new antagonist the same way the Friday the 13th series did with Jason in the sequel, instead they didn’t and people were asking for Myers back, if they had a well written new antagonist that scared and repulsed audiences the same way Myers did the late 70s/early 80’s then no one would ask for Myers to return.
The same way no one asked Ms. Voorhees to return when Jason took over. If Friday The 13Th part 2 was Halloween 3, people would backlash and ask for Ms. Voorhees back.
Halloween 3 should’ve been revolutionary if it was going to make the Halloween series an anthology. And Halloween 3 wasn’t, had it been named anything other than Halloween 3 perhaps the movie would’ve did better.