No. Never seen one. It's not exactly a bad thing though. And It's not uncommon among quality or luxury products. The idea behind it is simple.
Take a deal like McDonald's dollar burgers that get crappier each year, Subway's $5 foot long boosting freshness with well, quality and freshness a 5 out of 10 at best. They're just shooting themselves in the foot a little bit. They can in theory raise their prices like Arby's old 5 for $5 that is now something like 5 for $5.99+. But that didn't work out very well for them. Do you remember the 5 for $5? ever hear of their new deal, "choose five" or whatever it is? Nope. No one cares about it.
Could you imagine if GW regularly released products at a higher price and lowered them after they were a few weeks old? Then lowered them again after a year? Pretty much everyone would be waiting for at least the first price drop. They are quality items that are meant to be worked on for hours and kept for many years. If they had yearly Christmas sales, everyone would wait for Christmas to buy. The typical Warhammer hobbyist has a pretty good amount of WIP and unpainted models to hold out for sale prices. Just like hunting for Friday night pizza deals, they'd be creating a new standard. The average price would just have to go up. Just like the pizza shop's Friday deals raise their regular prices. They have a % food cost that they need to be making regardless of sale prices(GW % cost of goods). In the end, the the average price would be the same. And if everyone/most people wait, the sale price would become the current price. Most high end cars, clothing lines, and other quality companies fallow the same no sale model just as strictly. If Lamborghinis were cheaper for Christmas, their customers base would just wait till Christmas to buy, and their Christmas price would become their regular price. And the price isn't a factor. Qduba has a rewards program with no sales and JimmyJohn's has neither. They have a dollar sub day. But that is for promotions. They don't make money off that. And they both actually push quality and claim to be "fast casual" in an attempt to distance themselves from the fast food chains. The reality is, companies don't take the hit for COGs (cost of goods) ever. That phone you get with a two year contract, included in your contract and you pay for it monthly. Take that free drink/meal on the airplane. You bought it with your ticket. Etc.
As far as returning the old models rather than having a clearance, ties into quality. If they have a better quality model for you, that is the one they want you to own. Again, it's a product you are spending time on and keeping for years with their name attached. They provide only the highest quality models, oop is unacceptable for sale at any price.
I'm not saying GW's prices or business model is fair to the consumer, or isn't in general a crooked and evil company. But the no sale pricing isn't an issue. I'm not saying they are either. But I have heard a lot of bad stuff.