Well im in the UK, I'd say it isn't too difficult to find these games but at times it has proved difficult. When Zack and Wiki launched, I wasn't able to find it in GAME or Gamestation but I found two copies in Game Stop.
Also when No More Heroes came out, I had a pre-order set aside but I had a glance at the Wii section and there weren't any copies on the shelves nor were there any copies of Fire Emblem which came out on the same day.