There is even a crowdsourced version of the UI like artbot: https://lite.koboldai.net/#
And there are some excellent extant finetuning frameworks, like Aoxotol, that run on consumer GPUs: https://github.com/OpenAccess-AI-Collective/axolotl
IIRC Text-gen-ui had a QLORA finetuning UI too.
What I am saying is that its already like Stable Diffusion, but the community is just somewhat under the radar, and finetuning will never be quite as turnkey as dreambooth/sd 1.5 LORA due to the nature of the training data.