I'm not sure the point you are trying to make, the hulk didn't make Thanos bleed when Thanos still had all his armour on, with every stone he got he took more off, Tony drew one drop of blood when Thanos had no armour on. Thanos already had one or two stones when he fought the hulk, one of them being the power stone, the same stone that Ronin could have killed every being on Zandor with if he'd not been distracted by the dance off.
That's actually
exactly the point I'm making. Stark made Thanos bleed when the Hulk didn't make a dent.
And, yes, Thanos had the power stone already -- well, we know what it looks like when he uses that, thanks to seeing him use it against Captain Marvel. He didn't do that when he fought Hulk. Even if he had, he had one stone more when he fought Stark, which is probably how he threw a moon at him.
So, really, all that goes into my point: Thanos was even more powerful when he fought Stark than he was when he fought a being strong enough to literally throw the Hulkbuster around like a rag doll in those moments when Stark was not two steps ahead.
They nerfed Hulk -- severely -- starting in Thor: Ragnarok. As a writer, I get that they
had to do that, because Age of Ultron Hulk was so ridiculously OP that the villains who followed would have posed no real threat otherwise. And of course, I'm not saying they didn't nerf Thanos likewise. But had they nerfed neither, a full power Thanos vs AoU Hulk would have just escalated until Hulk probably hit Worldbreaker state. Narratively, that's clearly not what they wanted Infinity War to be, so they nerfed the shit out of Hulk to prevent that. Not to mention, Worldbreaker Hulk on a spaceship means a destroyed spaceship, and they sorta needed some of the other characters present to survive in order for the story to move forward.