Kind of meta, but you deserve recognition for this demonstration of self-awareness. You expressed skepticism politely, then asked specific questions instead of making assumptions. Sometimes HN gives me hope for the rest of the internet.
Sportbikes are lower, but they're not typical. Sportbikes sales trended way down over the past decade, with models being discontinued entirely in some regions. Current sporty-style bikes are generally more upright seating and share engines and platforms with non-sport models. Dual sport/off road bikes have trended upwards, even for riders who never go off pavement, because they're cheap to run and very practical as general purpose motorcycles. More recently, there's been a trend towards large touring bikes as well.
Somewhat yeah, the GS is a tall bike for sure. I have a zrx1200 and I'm still a ton taller than when I am in the miata. Miata is probably one of the lowest riding vehicles you can get and headlights are a problem at night shining in my eyes, where on the motorcycle it is not an issue.
Not really. Outside of a few groups at places like Virginia Tech, motorcycle safety studies don't get much funding. Too niche.
You can use insurance rates as a loose proxy- sportbikes are between one and three orders of magnitude more expensive to insure than adventure bikes, touring bikes or cruisers. But I suspect that has more to do with the average age of the riders.
And bike power. Sportsbikes are often road-legal versions of actual racing bikes, with all that it entails. If a third of cars on the road were tuned-down Ferraris and McLarens, you bet they'd crash left right and center.