[bonoboTP]

And simply TensorFlow was there earlier, so people implemented stuff in it. I think there's more inertia in industry, whereas researchers may more easily switch frameworks between two papers.

[amrrs]

And Keras was there too which made a lot of people us Keras with TF. I doubt if TF would have risen to this popularity hadn't it been to Keras.

[kuu]

Exactly this. Keras made TF easy.