I'm sorry, but this kind of posts make FF look like some kind of cult. And you make it sound like photos made with all kind of other formats aren't that important. I'm sorry but I find none of those cameras changed anything significant for any serious photographers, like other cameras before them and after them they were just normal progression. There is nothing magic about the format itself, and it does not exist because it is the best, or the optimum, in digital it exists mainly because there were many lenses made for that film format.
Sensor size is probably the least important milestone in digital cameras, it was just a natural progression and evolution nothing groundbreaking.
I think you are reading too much into this. Cult, no. But let's be honest, back in the days when the 1Ds was released it was sort of groundbreaking. Most cameras had smaller sensors with lots of noise and low resolution. Even today images from the original 1Ds can look fantastic (if used in good-ish light).
Today the format difference is of course still very real but not as significant since smaller sensors have improved
a lot and fast lenses have been developed accordingly for those who used to go for the shallower FF depth of field look. Fujifilm is good at this for example.