Yes, these shops hope you don't know that anyone can purchase the same carbon frame (direct, from eBay, or Aliexpress) and build your own bike. The bikes I've seen from Deep South and Lamere look like they purchased the frame from eBay. No custom paint, matte black finish, with some vinyl stickers slapped on the bike.
Not to mention, if I were going to spend $5k-$6k for a carbon bike, I don't think I'd want a generic looking Chiner. One guy at the trail, who was riding a Lamere -036, came up to me and asked if my bike was also a Lamere. He had no clue that I could buy a custom painted frame, with a BSA bottom bracket, and assemble it myself for half the price.
The other issue is warranty service and parts availability. If I didn't build the bike myself, paid over $5k, had no clue on how to fix it, and had to rely on an online bike shop to fix something under warranty (like the guy I met on the trail), I'd be pretty annoyed. I never had any real issues with my -057 or -036 but others on our forum have had some issues with things like the pivots on the -036.
The guy who bought my -036 pulled apart the pivots because he thought the linkage had a lot of slop and the rear end of the bike would flex quite a bit under load. He also said one of the bearings was loose. I explained to him that the bike was designed to be a lightweight XC bike, they frame was not designed to be super stiff and take a lot of abuse. My point being, he is coming to me for advice/info on the bike since he doesn't know anything about the Chinese frame, I pointed him to Chinertown but haven't seen him here.