Warren, I think incentive has a lot to do with it. One has to want to learn to spell properly and write grammatically. Reading has more to do with it than almost anything else, I think. If you don't read, you don't learn the correct words, you only pick up what you hear, and often hear the wrong words. As one of our government programs says, 'Reading is fundamental'. If you spend your time watching TV and playing video games, you won't learn to see words, and it's far more difficult to learn later. I don't blame the schools as much as I blame parents and the general environment. I grew up on a farm in the middle of nowhere, and there was no TV at all until I was almost out of high school. I read books to pass the time, because there was nothing else to do. Do something often enough, and you get good at it. Do it very seldom, and only when you must, and you won't be very good at it.
Probably the importance of spelling, grammar, and neatness in general is diminishing, because of the decrease in the ability of the public in general in these things. If teachers can't do it, how can the pupils be expected to learn it?