I think 30 mins is probably a v deliberate decision
1 - keeps the costs down
2 - keeps it like The Clone Wars Cartoon - i.e. it just gets on with it - 30 mins where stuff actually happens
Sure it could be 45 mins - add in 1.5 mins of beginning credits, make the montages a bit longer, add more as he travels "alone", and have more sitting around talking crap
He's not one for conversation, so there would just be 5 mins here and there of awkward silence.