It seems that every successive time I seek to advertise something on AdWords, the number of clicks in a given time period increases drastically, but the number of actual conversions brought about from those clicks drops (even for ads targeted to only attract clickers who have a high chance of converting). This means I keep paying more for worse results.

AdWords has become completely useless to me by this time, and I am no longer going to use it.

That seems to be a trend at Google: start out with great products, then let them decay until they are worthless.