Last year it was Stability AI that was presented as the leader in image generation, beating MJ, Dall-E and Adobe in various
sources and this year BFL's Flux model is touted to hold 42% of generations
alone. While I don't necessary trust these industry reports alone, I find rational that enthusiasts, like the people who're interested enough in the topic to argue on this board about it, would tend to use the cheapest solution, even if it involves more complexity (installing a computer program isn't exactly rocket science after all) than using a web service with a more expensive cost per generation, as they'd be generating a lot more images than average. At the very least, they'd use free models and just use website to rent GPU time to run them.