Mike, don't sweat it.
I have grown into the opinion that we all go through "stages". We progress slowly, then have"breakthrough" moments, followed by more slow progress, and then another breakthrough. Myself, at first thought I was really getting off the bike - until I saw the first photos and videos. Then I worked hard to improve body position but made only slight, incremental improvements. All of the sudden, a couple things "click" and there's a dramatic improvement - but wait! Then you're working on it more, but progress slows yet again. Kind of like "punctuated equilibrium". While I'm happy that my BP has really improved over the past couple years, I REALLY need to continue working on getting my darn head down (as well as many other things, as those who have ridden with me can attest to and often do). So, be patient. It does not happen overnight.
AJ is completely right. For most people if you try to focus in fixing "everything" all at once, it's too much sensory overload. Without great BP, it's hard to have confident control, so part of your focus is distracted because you're not comfortable with your entry speed, braking and lean angle, leaving less focus to deal with BP, and then you're trying to fix position on the pegs, weighting the inside peg, screwdriver grip, outside knee, opening inside knee, butt back and inside, body aligned with bike (not crossed up)....... Too much. Your brain (at speed) has the same "100 points of grip" as do your tires. Most people can find more success by focusing on just a couple foundational steps first, and then building on it. And maybe this will be controversial - but your technique is WAY more important than your pace when doing this. If you need to, back off the pace to build the foundation. Then you'll get that pace and much more back as you become more comfortable.
But at the end of the day, it's all repetition - and we all have different speeds and breakthroughs. Like with so many other things, recognizing that you need to work on it is the most important part. It gets you started and keeps you improving.