Julia came too late to the scene. When I first started using Julia 0.3, there was already Theano for Python, and Tensorflow was in the making. R for some reason

Julia came too late to the scene. When I first started using Julia 0.3, there was already Theano for Python, and Tensorflow was in the making. R for some reason is not as easily navigable as Python. The slowness of compiling Armadillo and Eigen makes it a no-go for iterating on new ideas. Maybe it should be asked instead why Octave didn't take hold, as Matlab is popular among engineering communities and the syntax is also simple enough to understand.