There’s no bypass button on some plugins/VSTi’s. This is just 3 of them but there may be more.
I tried 2 of them (marked with *) in Cubase 6 x64 and the bypass button was there.
Plugins: Cakewalk CA-2A x64, Padshop Pro*, BOZ Stereo Guitar Pickup Control*.
All of them are VST3 plugins.
Windows 7 Professional x64 SP1
Cubase Pro 8.0.40 Build 623 (64 bit)