He stuck around till he got his full reward paid to him which doesn't happen until RotJ, he only got a partial payment at the beginning of TESB, and as soon as he finally gets released from Carbonite, and got paid he split. That wasn't altruism, that was business.

Speaking of which, if The Rebels had paid him after ANH, instead of just giving him and Chewie an apparently "worthless" medal and medal-sash(?) , he probably could have paid off Jabba, and avoided the carbonite entirely.

I'm not discounting the fact that he came back with no reward offered. That is what makes Han a hero. Until that point he's just doing what he has to do to get a profit, because his ship needed repairs and those aren't going to pay for themselves. There's no dishoner in that, he's just trying to survive, and he doesn't think that The Rebels have any sort of chance against The Empire, since he has literally seen just how brutal The Empire is firsthand. This is a guy that ran away from The Empire so he could be his own man. He's not going to hitch his plow to some other group just because they have his ideals. He's more pragmatic than that, and they had to prove to him that they could, and more importantly would, stand up to this insurmountable foe that he's been fighting against, and mostly failing, for most of his adult life.

Han became a hero. There's no doubt about that. I'm not so sure Luke ever really did. Luke did heroic things, that's true. Luke complained about being forced into the hero role so much that I'm not going to call him a real hero. He's an unwilling hero. He never wanted this, and complains loudly every step of the way.

Han on the other hand never thought of himself as a hero, even after he became one. He's a hero not by choice, but by circumstance because he was on a path he never really has any control over. This is a guy who just wanted to make enough credits to retire to a nice peaceful planet, and the universe itself forces him into a position that, while he never wanted that, he accepts without much complaint and ends up thriving as a "General." I'm pretty certain that he literally laughs inside any time anyone calls him a General.

Finally, the praise Han deserves.