Oh yeah I never heard of chrono24. I'm not a watch guy at all :) I was just interested because I used to have casio watches when I was young. After which the mobile phones emerged and I stopped wearing a watch at all, until they started doing more interesting stuff (payments and notifications are what interests me mainly).
It's entirely possible that the more expensive "G-Shocks" were Mr G. I remember seeing wording about titanium cases, etc., but most of it was in Japanese, so the only thing that jumped out at me, were the price tags.
There are collectible models that sell used higher than they were new, but for the most part they’re much cheaper
Then there are lines like MR-G. hand hammered metal cases made out of premium materials.