Linear regression is an important part of statistics but is still ultimately a couple matmuls and a matrix inversion in its basic form.
Bayesian regression is often not really considered AI, unless it's incorporated in a more complicated pipeline (e.g. Bayesian optimization). Same goes for linear regression, then: alone it is just a model.
The term AI is about as concrete as "awesome".
Arguably that’s a different overload of the term “AI” the way it’s used in business, but I think it’s a good reminder that AI as a field has a long history that developed separately from ML and data science.