I remember when hot toys did an online poll for which character we wanted next. I think raiden mgs4 might have won. Solid snake mgs2 was like 2nd or 3rd. It was years and years ago now.I think Hot Toys was mostly to blame for the lack of figures, because they were prioritizing their Marvel lines over VGM. I also vaguely remember they teased an MGS V banner around 2013, but that apparently got scrapped.
When Kojima and Shinkawa were still at Konami, other merchandise was being released in droves. PAK especially made a crap ton of releases.... it was far from being a comprehensive list of all the characters, but it was still a lot.