My guess is it’s for the author sanity. However, if I had to come up with a reason to justify the author’s decision, I’m gonna go with – he has an endless supply of anything in there. Which means he can wear that same outfit 100 times a day, and it would be brand new each time. Therefore, considering it’s the apocalypse, and the guy has 1 million things to do and worry about, maybe the MC just doesn’t wanna deal with figuring out what to wear that looks decent. So he’s just putting on the same outfit again, and again, and again… because, priorities and stuff.
Fashion vs people’s lives… ╭ ( ̄へ ̄) hmmm, decisions…

Like I'm at chapter 52 but he's still wearing the same thing. WHY (not really important but like why not)