Yeah, because last year, everyone did that too, and none of the exclusives are doing much out of the gates. Sure, you could sell your red 5s and make about a 10% return, but overall most of those sets have hit a wall compared to previous years. Expecting this years crop to perform better than last year? Well, then some might have taken the blue pill, but I choose to be more realistic.
I do think some sets HAVE potential, don't get me wrong. Lego will retire hundreds of sets, and of those maybe a handful (like 10) will do something interesting and make people money. But, that's a lot of hit and miss that keeps getting a larger ratio every year. In the end the sets everyone thinks are going to do well, will in turn be horded by more and more people since others will be thinking they have the next 3x set, and in the end the oversaturation of resellers will cause it to stagnate and not even hit last years levels.
So, am I excited that Ecto1, or Pet Shop is retiring? Not really. I love the Pet Shop, don't get me wrong... it's a fun build, and a beautiful set to look at when done. But, so many have them waiting to resell them, and if you judge from the previous modulars that went out into retirement, well while they have doubled in price over a two year period, there's no saying that the Pet Shop is going to perform better than GE, or the FB! More than likely it wont. More than likely it will take 3 to 4 years to reach that level, and after fees and shipping (which goes up every year), whose to say by the time it finally does hit the 300.00 US mark, that it will net the same gain that selling a GE would during the same time frame. More than likely it won't. At that point you are holding large sets that take up a lot of space, and making less and less money as each year goes on.