Most of the "cheats" you're talking about are actually glitches. It takes a lot of time to go through a game and fix stuff that isn't working properly, and with the submission system in place here at AG, it's almost impossible. Most of the time it's fixed in a sequel.
True, glitches do appear alot, but I think he is talking about actual cheats that were made by the programmers. The first example that comes to mind is SMO Arena, with the profile name cheat. If create a profile with the name "fungus," when you use it you can use all of the guns and go to any level. It seems to me that it was put in so that the creator could test all of the weapons and levels in the game without having to play through it, then forgot/didn't remove it.
Can't you just play the game normally how it was supposed to be? I mean, is it that hard to play a game regularly or do you have to hack it because you are to lazy to play the game? I used to hack, all i can tell you is that it is boring finding the right codes, it is way easier to play the game regularly, that's why i hate hacking, it is so dang boring AND is just ruins the whole game!!!
ubertuna, he meant to say glitches and cheats. The creators sonmetimes do fix the glitches, but like Tydus said, it is very hard to fix them. Besides, of someone wants to truly enjoy the game without taking advantage of a glitch, then he/she can! It does not make much of a difference unless you want to get a highscore.
If you don't want to use them, you don't have to. Some cheats are put into the game for fun... one that comes to mind is an 'infinite money' cheat on one of the arcade shooter games. The 'cheat' was explained in the directions, to add another level of fun. You can either play the regular way, or just play around with the infinite money.
As for glitches, this is one of the main reasons that we have the ability to review games. There is nothing better to test the rigors of a game than having an entire website play it! If you see a glitch, mention it in your review of the game, so if/when there is a sequel, the dev will realize it and fix it and improve the game.