With me there are a few things that have an effect on ball to ankle distance......early turn, targeting too far right from where I am lining up (right handed)and muscling the swing all cause me to get away from my ankle.

I am not a perfectly coordinated robot or have narrow shoulders........but I am quite a bit closer than 7 boards and I haven't slammed the ball into my ankle in 20+ yrs. If someone has the ball 2 feet from their ankle they are losing tons of leverage......just because they are doing it doesn't mean it's right.  Doing that the ball must be outside of your head and no way they are creating optimum power and they are losing accuracy.

I guess this is something I shouldn't try to change since It isn't broke.

Seven boards is good. Many years ago, I was around 9-10 boards. This was causing
leverage and accuracy issues. I went to see Fred Borden . He was instrumental in getting me to close this distance. Today, I am at 5 boards and have been for the better part of 40 years. PBA legend Don Johnson hit his ankle with the ball at a PBA
stop. The ball bounced off his ankle and went into the channel. Afterwards Don said that
hitting his ankle was no big deal. In fact, he said he remembered thinking to himself
that hitting his ankle was not exactly a bad thing because it was an indication that
he was keeping his laydown point close to his (ankle).

Of course, hitting one's ankle with regularity is NOT a good thing and measures should be taken to correct it. However keeping that distance to a minimum
will definitely improve your accuracy and leverage. Before the days of reactive resin,
exotic cores, synthetic lane surfaces and "crowned" oil patterns, this was an absolute necessity. It is still very important today, but not quite as much, because in
most cases modern equipment/ lane surfaces/patterns will permit a LITTLE more
"slop" in this distance--but not much.

Regarding the dropped shoulder, most of today's power players actually benefit
from it due to their swing mechanics. If you are an old-time stroker, as I am,
excessively dropping the bowling shoulder can create a host of problems.
Since a stroker relies more on accuracy to get the job done, excessive lateral
spine tilt creates too much "play" in the swing  because the bowling arm
now has too much side-to side instability. It causes the swing to deviate from its
optimum plane or "slot". My lateral spine tilt is around 15 degrees (from the vertical).
This keeps my arm close to my body and ankle and increases my ability to repeat shots. Dropping my shoulder beyond this amount results in the problem above. A power player benefits from doing precisely the opposite due to their hand position and their ability to throw it to the right. 

I have videos of myself with the ball touching my shoe laces. So my ball is within a 1/2" of my ankle. I haven't hit my ankle in years, but then again I'm not thinking of that while on the approach 😉

For what ever reason, my problem is the opposite in that my ball is too far away from my ankle.

It has to do with the ball staying closer to your center which at times has to do with your swing shoulder being lower than it's opposing shoulder...staying square tends to force the ball on the outside creating an inside out swing plane (generally) or away from your ankle...
This is the misconception with square or level shoulders...I would try opening up your stance at address to mimic your finishing position and dropping your swing shoulder a few inches lower to allow the swing to swing closer