I get these too. At first it looked really bad, I thought I was ruining the finish, but then I cleaned the gun and all of the streaks had wiped awayAfter a couple months, I have a little bit of wear/shininess on the trigger guard of my Glock 27 from where my Supertuck grabs onto it for retention. I have no problem with this. I also get these mysterious shiny metal steaks on the top of my slide that I cannot figure out how they are being caused. They wipe off though.
Felt and suede used to be used as liners on leather holsters 20+ years ago, but was discontinued because they picked up and held dirt, scratching and marring gun finished far more than plain leather. There are a couple of makers that line Kydex with thin, smooth leather, but most don't.I understand there will be wear... and for my carry guns it is no biggy. I guess I'm surprised that the inside of the plastic isn't lined with felt or something else that would reduce wear w/o affecting draw times, etc.