A lot of the really expensive high end designer clothes don't really have any logos on them or if they do they are very small for this very reason. Due to this what they wear might look conservative but could be expensive as fuck ;)
That exactly. Which is probably the same thing that several others have pointed out..
A 100$ shirt will have huge logos all over the place because the market segment it targets are people who can "just" afford it and want to signal other people who can't.
A 1000$ shirt will have little to no logos and will be distinguished only by "others" who can spend as much, because if you wear 1000$ shirts why would you care signalling to the person who can "just" afford 100$ shirts that you have so much more? You may care to signal this to other 1000$ shirt owners but then maybe you just don't care about signalling via clothing ;)
A lot does but it's subtle and only those "in the know" can identify a particular designer.