Steinberg (now owned by Yamaha) does not offer older versions like 7.5 for free. Unlike some indie developers who release legacy software as abandonware, Steinberg still holds a tight copyright on all versions back to Cubase 1.0.
Cubase 7.5 introduced the revolutionary "MixConsole" which brought channel strips and a dynamic console view to the DAW. It also included "VCA Faders" (borrowed from large format analog consoles), "ASIO-Guard" for better CPU performance, and "Chord Track" enhancements. Cubase 7.5 Free Download
: An updated version of the drum sampler, offering lifelike drum kits and inspiring beat-building tools. VariAudio 2.0 Improvements Steinberg (now owned by Yamaha) does not offer