Hehe, true! I left the field about 4 years ago when it became obvious that "more GPUs!" was better than any architectural design changes...
Most of the image generation made by the products you mention are based on a mix of LLMs (for processing of user inputs) and some other modality for other media types. Last time I checked, ChatGPT was capable of handling images only because it offloaded the image processing to a branch of the architecture that was not a transformer, or at least not a classical transformer. They did have to grift CNN parts to the LLM to make progress.
Maybe in the last 4 years they reorganised it to completely remove CNN blocks, but I think people call these models "LLMs" only as a shorthand for the core of the architecture.
Again, you said that a new benchmark is set every few months, but considering they're just consuming more power and water, it's quite boring and I'd argue it's not really progress in the academical/theoretical sense. That attitude is exactly why I don't work with NN anymore.