I think you couldn't care less and yeah, because a $200 vs $4 white tee is a great example.
Anyway, they're almost definitely not 50x better in material & construction, fit, etc to justify the price but...you can very easily find higher quality Egyptian cotton t-shirts from a company like Sunspel which are clearly much better (I've gotten a couple on sale for less than $30) and have retained that softness over many washes than a 5 for $20 Hanes t-shirt. If you can't see and feel a noticeable difference especially after washes, that's on you. Even J Crew's Jaspe t-shirts that are around $35 and you can usually find on sale for like $20. Some people are just frugal (read: cheap) and might not appreciate the differences in the two or do everything they can to justify their unwillingness or inability to spend more. That's not to say you can't get by with a Hanes t-shirt, I have one on now that I wore to work out but the collar is all ****** up, it's shrunk about a size and the material has clearly changed its feel over time.
That's just one example because you brought up that extreme with t-shirts. You also get what you pay for with dress shirts and I'm not talking $400 shirts but even the difference between one from the previously cited H&M compared to Canali or even Hugo Boss which aren't even that expensive. I could go on with so many more instances (polos which you now brought up, jeans, even socks) but it's really not worth it. Throw on some bright-soled wannabe Lunargrands and kick rocks.