Earlier quoted context omitted.
I think it's more likely this is just a niche that Midjourney has occupied.
If Midjourney is a niche, then what is the broader market for AI image generation? Porn, obviously, though if you look at what's popular on civitai.com, a lot of it isn't photo-realistic. That might change as photo-realistic models are fully out of the uncanny valley. Presumably personalized advertising, but this isn't something we've seen much of yet. Maybe this is about to explode into the mainstream. Perhaps stock…
Replace commercial stock imagery. My local Home Depot has a banner by one of the cash registers with an AI house replete with mismatched trim and weird structural design but it's passable at a glance.