Aren't leaks and memos from the past few month implied that GPT4 won't be multimodal, but rather last shot at what can be squeezed from text-only model?

Most of multimodal developments happened quite recently and probably won't be incorporated into GPT4. I do not know how long does it take to train a big GPT, but I assume it's a quite long process that takes many weeks if not month. And these things are not trained on bleeding edge AI architecture, but rather at something that was approved during project planning, which, in case of GPT4, happened many month ago.