You seem to be approaching this as if it was NECA or something. Most people aren't going to spend $240 on a Clara Clayton figure or 1955 Marty or Biff or own multiple DeLoreans. Sure, there's going to be a few who would, I would love a Clara, Bufford and Marty and Doc in western gear but that's not the way Hot Toys operates. Even massive sellers like Iron Man have some big gaps in their lines. No Killian from Iron Man 3, or Happy Hogan. Batman V Superman didn't see Lex Luthor, Lois Lane, Bruce Wayne, Clark Kent or Doomsday figures made. The list goes on. They do a few key characters and move one because every Marty they make takes up a spot in the factory where they could be making a new Thor, or Darth Vader or Batman which is going to sell massively more than any BTTF figure and those figures need to be out at a certain time while the film is still relevant.
As for the DeLorean those extra parts to make all the variations would have driven the price up more and probably would have meant even less sales. As you said, Marty and the DeLorean didn't sell as well as expected. At the end of the day Hot Toys is a business and if a line isn't doing well for them it's kind of silly to expect them to delve deeper into it, isn't it? If Marty in his iconic outfit from Part I didn't sell well then a Johnny B. Goode version isn't going to do any better, would it?
Yeah, Hot Toys has handled this licence wrong. No BTTF Doc is a mistake, as is showing the hover DeLorean before the first is out but as someone who also has been wanting Back to the Future figures my entire life getting one very good Marty, one decent one, a Doc Brown and a very nice DeLorean to go along with them is more than I had for the first 30 years of my life.
