I'm going to disagree. If you are trying to QFLL, then yes, you are correct. You shouldn't be looking at items like exclusives as something to maximize your funds and your space.
But, if you are investing, then it is efficient.
Here's why: Just this week, I sold two sets that were some of the first investments I made. I made 2-2.5x my buy in on them. They were not smart investments. I bought them before I even knew there was a forum here. (I wouldn't find the forum for almost another year).
Now, imagine that you've been slowly buying over the last two years. If you're smart about what you buy, you can start selling off for 2-3x your buy in. You're making nice profit. And you just keep rolling.
It takes time and commitment. But, if you start and plan ahead, then you're on this rolling cycle. That's certainly been a strategy I've tried to employ - buy and hold for at least two years.
Sure, I get involved in the QFLL stuff all the time. But for my investment purposes, it's buy and hold, and hold and hold and hold. I'm not worried about PS retiring, because I've already hit my (small time) quota on it. When I'm talking investments, I'm going to buy stuff that I will hold onto for awhile. And I've got to manage it smartly - I only have half of a garage to operate in. And trust me, I have to get creative, and every couple of weeks I exclaim, "I won't buy any more Lego - I'm out of space!" and yet, I still manage to find space for things that I know will be sitting here for a couple of years.