@Kynnath So just to elaborate a little on a real world implication of the MC retiring from a career at 17. He's spent the last 7-8 years MINIMUM on stage, preforming magic for the masses, and becoming a world wide star. It's entirely likely that had he not died, the retirement would have been completely warrented and worry free, seeing as he likely had plenty of money saved up and propperly invested from his many years of preforming. There's part of Chapter 1 that even shows that he was able to spend upward of 50-100k yen on something that turned out to be fake when he was only 10-11 and still live in a very fancy and rich appearing home.
It's not impossible that he was rich beyond belief and was just tired of the showmanship being wasted on people that just didn't care about it and were more or less viewing him as a glorified idol because they KNOW all the "magic" he does is fake and they can just look it up live to see how it's done if they really want to. You can't really say that if you were in his shoes and had spent a majority of your young life on stage preforming, only for the masses to no longer truely appreciate your craft that you wouldn't be sick of it and would continue doing it, especially if you had invested properly and had a manager that actually cared about you enough to make sure you don't get conned a second time when you're incredibly young.