I’m not sure what you mean by this.
We agree, and are working to develop a solution that’s device independent, which should go into beta at the start of next year.
In the meantime it’s possible QGC could work, it’s just not something we are actively working on to make sure it works consistently across mobile devices and tablets, so there might be issues / sub-par performance.
You could also look into ruggedised Control Station Computer options, and/or third party Control Station Software alternatives 
It may be possible, but I don’t believe there’s an installable download available - you would probably need to compile QGC yourself. There may also be issues with insufficient RAM and/or processing power.