Depends on the market, but a few things come to mind... music streaming, movie streaming, smartphones, social media, electric cars, SaaS as a concept, LED lights... They all have one thing in common: They serve a specific need or specific improvement of existing technology. AI on the other hand is marketed as the "improves everything" machine, but what it really does is creating a shallow copy of existing technologies and ideas. In most cases by doing a worse job than the original. It aims to mimick existing things. That in itself is not a killer app. It's just a faster, cheaper, sloppier way of doing things we are doing already.

Btw, I'm not talking about Machine Learning applications here, they are a different animal. What most people think of when talking about "AI" is just LLMs