I don't know if that first part is true? Classifiers were/are one of the dominant applications of classic ML and neural networks, especially in production. Even today, image classification, object recognition, language detection, segmentation models etc are still super common.

I think the hype with Jev is just that, while structured generation is great, LLM judges tend to kind of suck for precise classification. And the more powerful the base model, the more accurate they can get, but they get increasingly expensive/impossible to finetune. It was specifically the latency/price point Jev offered vs. the general accuracy it claimed that generated all the excitement. Plus the promise of cheap calibration (tuning).

"Jev exists because LLMs exist" is kind of a truism, as Jev apparently is literally a Transformer model.