1. Is this acceptable practice instead of having 2 to 3 kw phrases per page?
It's fine; the more content you have, the better
2. is this practice considered spam?
Only if the pages are very much the same except for your key phrases
3. will site traffic increase?
Possibly; definitely if the content is unique, original, relevant to your key phrases and interesting.
4. am I wasting my time doing this?
Possibly. Can't tell without seeing what you are actually doing. But from your account, it sounds as if your content is 100 variations of one page, rather than 100 different pages - if I've got that wrong, I apologize.
But if I've got it right, even if you increase your visitor numbers, that just means a greater number of disappointed visitors. They won't stay, they won't revisit, they won't do business (or whatever else you want them to do).
So if that's what you are doing, it's a complete and utter waste of time, effort, bandwidth and anything else you care to name :)