It will be very hard to displace Matlab out of certain very important niches. For example, across both academia and industry, Matlab is king in control systems design/analysis thanks to its toolboxes, Simulink, and (at least in industry), its autocoder. Matlab is used to generate the flight controls software on a lot of today's aircraft. In a number of other engineering disciplines, Mathworks has been astute in developing toolboxes that answer the needs of industry. There will probably have to bit quite a bit more paid development of Julia and its ecosystem to deal Matlab death blows in industry. I hope for it to happen sooner rather than later, as the 70s-era Matlab language and Mathworks' exorbitant license fees are holding things back.