Unfortunately, even if octave can replace MATLAB the language, it's going to take herculean effort to replace MATLAB the ecosystem. Replacing Simulink alone is

Unfortunately, even if octave can replace MATLAB the language, it's going to take herculean effort to replace MATLAB the ecosystem. Replacing Simulink alone is a huge undertaking, let alone trying to replicate SimMechanics, or some of the other more niche toolboxes. Being able to run a control system block diagram on arbitrary hardware (ARM boards, etc) is huge in the controls world. The places I see using MATLAB today rely on Simulink & SimMechanics, as well as the Control Systems toolbox and the computer vision packages. OpenCV can replace some of the CV stuff, but can't provide an integrated solution for the controls portion.