Actually there's more suit-style millennium godzillas around than concept. Not one marmit or sofubi type vinyl is in the millennium concept style. there are a couple of high grades, an xplus, sh monsters, and banprestoS in this style, no hypers in the concept style. But there are numerous g 2000 style godzillas both from the millennium film as well as the megaguirasu film.
Even with 89/91 Godzilla many versions can be considered stylized, but i believe it has more to do with the attempt to capture the right look. Neca had a horrible time trying the get 84 right. They barely got the look of 94/95 and the only one almost right is 2014. Even their GMK is off but I'd hardly say it's a particular style they are doing anymore than saying the Japanese do a manga style which I've heard time and again re Medicom figures. I chalk it up to the pop culture...for example I've noticed lately that kids who grew up on Japanese anime tend to sketch using anime shorthand vs the guys who grew up on marvel and DC comics who sketch differently. The inflUncles are subconscious tend to ctoward me out because it is what helped shape that artists style...even when he or she is inaccurate.
I even think xplus got 2014 better than Sakai...which is rare.