Do we really need 6GB RAM on the phone? I have a phone with 1.5 and a tablet with 4 and it's the same thing in most cases. Android doesn't do multitasking so the only noticeable difference is when starting something demanding and huge. But part of that also lies on way faster SOC on tablet and not just the fact that app is frozen in the background.
And for sailfish............ well, there's not enough app to fill that RAM anyway