Supply and demand probably- how many anglers and videos link to tacklewarehouse? How many times have you looked at an item on tacklewarehouse and it was sold out?
I see more tacklewarehouse shirts, hats, gear and stickers than just about any company other than Cabelas/BPS. They have all the exposure they need and probably realize with their volume compared to out of stocks they can raise prices to increase their profit margin. It also allows them to do more promotions, coupons and sales.
I do most of my business at a local shop (Wacky Worm) anyway and never really complain about the prices because it's great having the convenience of a local tackle shop that has everything I would ever truly need and advice from an angler. If it's too expensive I just don't buy it.