A blued gun will be worn down to bare metal in these spots after relatively few draw/holster strokes.
While possibly true, i'm not entirely convinced on the "few". Methinks the holster is much too tight.
I have been carrying my Colt New Agent .45 in a CrossBreed Supertuck IWB holster, which is horsehide/kydex hybrid. I draw it every time to put my holster on, and then replace it. I've been doing this 3-4 times per week for about eight months now, and the only markings I can find on the gun is the very front of the slide where my pants themselves have made the finish slightly lighter (and it may have always been like that), and a pinpoint mark on the front of the triggerguard where the gun is supported. If I clean the gun with a Hoppe's #9 silicone cloth, the marks disappear. It's almost as if the marks have been made by the same abrasiveness as a fingernail. The effect may be pronounced with different holsters, but my CB treats my gun very well. And I know my Colt is an expensive piece, but I didn't buy it to put it in a display case; I bought it to come with me wherever I go. Yes, the sad truth is your gun will start to get a little holster worn, but the easy solution is this:
If you want your gun's finish to stay beautiful - Keep it in a nice padded case and use it for range only.
Get a carry gun that you won't feel bad about carrying. I'm not saying beat the tar out of it- just don't sweat it when it gets a little holster rash.