You see nothing wrong with deceiving your players? Or being deceived as a player? You are far more forgiving than I. As a player, I do try to have at least a few ideas of things I would like my character to do, such as my priest who wanted to start his own cult and therefore needed the leadership feat. If the campaign never reaches 6th level, then I can never do that. All I can do is plan for it and dream about it.
While that may be fun for a while, at some point I would actually like to attain my dreams. What's the point of playing a fantasy game if I can't make my fantasies come true?
The limitations on the levels is most certainly not built into the game itself. That's simply not true. There is a huge amount of support for higher level games whether from WOTC or the d20 crowd. There are more than a few threads floating around here on how to handle higher level play as well that are chock full of good advice. Never mind that you've now got three adventure paths that are going to lead into the high double digit levels, as well as any number of modules being offered in other venues as well.
The days of there only being two or maybe three modules for 10-14th level play are long behind us. The rules are there to be used and, believe it or not, do actually work without half the group being left in the dust.