Listen, I don't think there's a conspiracy here.
What I think happened is that Luck suffered a mild calf injury, but it either wasn't treated correctly initially/didn't heal and it complicated (much like lower leg injuries do) into three separate things working in unison--so even if you treat one, you still are dealing with the other two--and they're all causing pain so it's hard to know what exactly you're treating.
A report said Luck can walk normally in every day life relatively pain free. However, I think he didn't want to exasperate the issue any further by playing professional football and perhaps making things worse than they already are (by putting more physical strain on it, opponents twisting it during a tackle, etc.).
I don't think the anti-inflammtory thing is as much that he's worried about drug addiction, as much as he doesn't want to spend the rest of his life dependent on anti-inflammatories in everyday life--should the condition worsen.
The dark days of 2016-017 to me were less about drug addition, and more that I think Luck played through pain (cracked ribs, etc.) in order to save other people's jobs. He felt responsible for saving Pagano's job, Grigson's job, and tried his best to get his teams to the playoffs because he's their best player and he was good enough to carry them pretty damn close to the finish line. That's a ton of strain to put on yourself when you solely feel responsible for everyone. Luck even said in his presser, "I promised then that I wouldn't do that to myself again" or something to that effect.
I also think just constantly rehabbing and getting close to the end only to experience setbacks, only to start a new one entirely would be pretty draining. You tend to be isolated in those situations and away from the team. It's like getting ready to scale a mountain, but never making it--only to start from the bottom again.
I also think that Luck has had so many lingering injuries as of late that even if he rehabbed this one, who's to say another issue wouldn't pop up?
If there's an actual conspiracy here, I'd venture to say it's more like Luck is still experiencing pain with his throwing shoulder or knows that he's lost some zip on his fastball. Something physical that's still working in combination with the ankle.