For the knife experts out there...

Does the quality of a steel change toward the the top of the knife vs the edge? I sharpen my knives often and some knives just don't cut the same as they used to, and I'm not really sure weather it's because my edge is getting thicker at the top and needs thinning out or if the steel just isn't as great towards the top of the knife. I'm assuming that it's the former, but for some of my knives, they feel completely different from when I 1st got them, making me believe it could be the latter.

I'm hardly an expert but may give it a try. Excepted for expensive honyaki knives who are differentially hardened, the steel is the same. Thinning is a normal part of sharpening. If you never did you have an axe with a fine edge. It's a common phenomena with jig system users who look at the very edge only, and so neglect the whole geometry.
Another reason for less performance could be fatigued steel. If you've used medium stones only you never had fresh steel. What are the knives, and how do you sharpen?

If you aren't thinning as you go, sharpening (removing steel) from the top of the bevel down to the edge, then you can create a wedge shaped edge over time which reduces performance. That could be one thing. Another possible issue could be your technique on the tip. It was an area I had to work on a bit to get better at it.

Stop pressing so hard. I'm willing to take a blind stab that you putting too much pressure on the knife when sharpening the tip.

I've had a few conversations with knifemakers about this, as well. It comes down to how "deep" hardening the steel is but generally, it shouldn't affect performance too much. I'd say you need to thin or otherwise regrind your knife.