Having had the AWD Sequoia I can 100% tell you that you had no AWD unless you were in 4high. My Landcruiser was AWD given it was full time 4high all the time.No... that's not what AWD means.
GM and others offer 2hi,4hi, AWD, 4lo from the factory. Just like Toyota did in some 3rd gen 4runners and some 1st gen Sequoias. They also offered AWD, 4HI, 4LO in v8-equip'd 4th gen 4runners.
GM offered a AWD button that basically turned on 4hi when traction issues were detected yep had a suburban with that. Basically GM let you choose to have 4x4 high turn on if you start spinning tires aka soccer mom switch that dad turned on every winter and turned off every spring. Again its just 4hi getting turned on.