Thats different dude, Luffy did the most for them in their arcs, they feel indebted to him thats why they joined him. And Luffy is a pirate and he is not a normal leader, He puts his life on his sleeve for his goals and expect other to be on par with him, Sailing the grand line and going to the journey to be a pirate king is not easy, he is ready to die for his goal and everyone in the crew knows that. But Luffy would still protect his nakama with his last breath, he declared war on world government for Robin, fought countless opponents more powerful than him, His crew expects nothing less than him. its Luffy who is doing the most and is always at the forefront against danger.
none of the crew members joined out of a gratitude, it was their own choice to go out to pursue their dreams alongside luffy, zoro's case was different because he joined luffy because they had a deal, all of the crew members had dreams that requires them to sail around the world, they just had some obstacle that needed to be dealt with through a collective effort of the entire crew.
-saving nami was the crew's decision, they were there for her before she even asked.
-the enies lobby incident wasn't luffy's decision alone, all of the crew were ready to sacrifice themself for robin, usopp wasn't even a SH.
all of the straw hats are good natured people, sacrificing theier lifes for each other is a given.
when i talked about luffy's selfishness, i meant doing things that deliberately puts the crew in danger, in skypia he even wished for nami to drawn because she could ride a dial boat better than him which was funny as hell.
luffy's dream is always given great value by the crew whenever someone talked bad about him, but we never saw luffy do such thing for them. luffy just sees zoro's dream as a requirement to be in his crew, the others just straight up changed their dreams.