By the time the sets are in resellers hands, LEGO has made their money. We've talked at great length about his before .. whether LEGO likes resellers or not, whether scarcity of product is good for their image or not, whether higher secondary market prices allow them to raise their prices. etc. In the end, we just don't know but love to speculate.
As for the Taj Mahal, is it being unhappy with scarce sets or was someone thinking - you know, we've had a down year and had to let some people go.. We just don't have the time or money to do new designs for every market segment we're trying to reach... what if we re-release a popular but rare set? A few die hard collectors will be upset but we'll be making a larger part of the market happy. Less design time, update the packaging a little, boom, easy money. Or did they say - let's make people happy and release a set from our vault no matter whether we make money on it or not!
(I know that's dramatic, but in the end they do this to make money...)
Just look at the death star fiasco... giving it a new number and making some extremely minor cosmetic changes blew up in their face PR wise. Sure people are buying it because who doesn't want a death star, but it was not the happy reception they expected. People -rightly so IMO- saw it as a money grab. I know minifigs aren't that kind of money grab, but its one of the only things they could get away with in the "mystery loot" schemes - which companies do to make money. Who'd buy a box of random lego blocks unsure if it built a car or a boat.
The average buyer doesn't give up and just go to ebay... it's part of the attraction to "just one more time." It's addictive just like gambling (no, I'm not saying LEGO is gambling). I honestly think LEGO likely approaches it this way: it's fun and will make us more money. People can't just buy the one they like but they'll have fun trying to find it. I'm pretty good at smooshing the bags (smooshing is the technical term for feeling up the bags) but it's time consuming.. it would be a lot more fun to just buy them blindly.
Given the odds of finding the CMF(s) you want in a retail store vs some of those online games (gachas), the odds are pretty good... And there have been some well documented cases of companies making the rare items even rarer than advertised - LEGO doesn't do that. In fact, by shipping them in cases of 60, the true distribution becomes known very quickly vs companies that do not disclose the rates at all. To me that shows two things .. 1) they do care about customers and 2) they know this is good enough to make their money on them.