I think people are missing the point that the idea that Lego sets hold and even increases in value helps Lego enormously.
Even before the concept of AFOL's and Adults sets this was the case. When I was a kid Lego cost more than cheaper toys but my mum would say "Lego lasts you can pass in down once your done with it.
How does Lego get people to pay £650 for a Lego set, by have perceived value. If you have it in your head that a UCS MF cost thousands then hundreds seems like a good deal.
Lego also does well from collecting, the I need to have them all mindset. I think by making lines too large and having too many large sets Lego are oversaturating the market. If a line has 6 sets you might try and buy them all but if you feel its impossible to buy them all you might only get a couple and Lego loss sales by having too much choice. Also if a 3000 piece set is normal then you don't get excited about it.
How many of us buy a set because we might want it one day and we don't want to miss out because the after market price becomes too high. If aftermarket prices become too reasonable and if the best sets get remade ever few years then I can just wait.
Lego do profit from the after market and that's before you even consider people buying Lego just to resell. I think Lego are really harming the long term AFOL market.
I don't own the Taj Mahal and I am not a reseller so I don't have a vested interest. But I am a collector and a completest and after this year I will be changing the way I buy Lego because I can no longer complete a lot of my collection and Lego have harmed the collecting side with rereleases.
Lego got a lot more of my money this year then I intended but the consequences will be they will get a lot less next year. And I wonder how many people will have the same reaction. I think the Lego bubble is just about to burst.
And to end with a bold prediction, you will still be able to buy a Taj Mahal the day after its released unlike the MF.