If you think about it in the next 10 years or so probably about 2 more (or no-one) people will submit to Sonic Rush Adventure and that's it.
Fixed.
Okay, let me play the same game here. Sonic Rush Adventure is still on the market and has a chance of gaining, as you put it, maybe two more people competing in the Extra division. It currently has 14 competitors with 300+ stats submitted to it. Sonic Jam is no longer available for sale and has a near-zero chance of gaining more competitors. It currently has 10 competitors with 68 submissions.
...hey, let's remove Sonic Jam from the rankings!
You want to remove a single division that's had way more effort put into it than an entire game gets. From my point of view, if people don't want to put in the effort to fill out their charts, you can't take away the work done by the people who do work at it. I know it seems selfish of me to say that when you're in the same boat, but laziness has never been an excuse before, and it shouldn't work in people's favor now.