The cosmic carrot is a very real experience in people's lives, and in people's beliefs. At least it seems to be for me, and I think for others. I think the explanation of why the cosmic carrot is a little more complex then that described above: the carrot isn't something that the priests and elites invented to deviously channel the hedonistic urges of the peasants and masses. It is a byproduct of the way the human mind seems to function.
To explain this, I will begin with a mundane example, the game of solitaire. Not an entirely trivial example: solitaire probably takes up more time than more obviously hedon generating activities, such as sex, eating hot fudge Sundaes and sky diving. For all that, there is no apparent hedonistic reward involved in playing Solitaire. If you are playing Windows Solitaire, you get to see the cards bouncing. However, people could probably, if they so desired, find a movie of this online and replay it over and over again, if that was their goal of playing solitaire. Or for those still inclined to play solitaire in the real world, they could always just arrange the cards in neat little piles. If the chronological ending of solitaire was the carrot of solitaire, people would skip playing the game. There is a reason that solitaire has an ending though: it provides some kind of narrative structure to the game. People have a natural tendency to form patterns and tell stories. Solitaire, in its own way, combines both. The chronological ending of solitaire is just there to provide a narrative structure for the pattern formation.
Solitaire is a very basic example of what is true of many human activities: the stated goal (in the sense of chronological ending) is not the real reason for doing something. We could view human life as a random series of encounters, unconnected to each other, meaning nothing and leading nowhere. That would be the equivalent of just randomly putting cards into little piles that looked interesting at the momemnt. Notice that random card piling never caught on the way solitaire did. In a life full of random incidents, relationships, encounters, events, disasters and epiphanies, the human mind automatically reaches for something to bring these things together. People don't necessarily believe in apotheosis or The Promised Land or self-cultivation or having the most sex before they die because they want those things, as much as it allows some kind of narrative perspective on the patterns that already exist inside their lives.
There are times, however, when I can imagine a life with no "end" to it, a world drifting inside the endless Be Here Now. Those experiences are one thing, the rest of my life is another. Personally, I think anyone who can live without a cosmic carrot is either an idiot or the sage. Those of us inbetween must rely on some idea of a transcendent goal.