There's always an adjustment period when transportation options begin to shift rapidly. If you go back and read newspapers from 100 years ago, you'll see people complaining about how cars are a menace and don't belong on the road with horses. Based off of some of the stories about how recklessly people handled some of those cars, you might even be inclined to agree with the anti-car crowd of that time!
However, just like with cars, banning scooters altogether is probably not going to be a widespread outcome. The reason scooters are so popular is because they actually do solve a crucial missing link for many cities, especially southern cities which often have terrible transit options and patchwork sidewalk and bike paths. Then you factor in the crazy summer heat and humidity, and it's no wonder that people are into the idea of a quick, breezy, ride that can navigate on either roads or sidewalks.
Here in Raleigh (which is a fraction of the size of Nashville to be fair ), there is a major problem of pedestrian unfriendliness the second you leave the downtown core or college campus area. The sidewalks are spread out thinly, often only existing along major arterial roads which are hard to cross, and then often only one sidewalk on either side. The back roads which would be safer to walk on in real cities normally (due to having less traffic), typically lack sidewalks at all. So you end up with your options being big empty, sidewalks with no shade or benches alongside cars going 50mph (on a road that doesn't usually have actual houses on it) or tighter roads with no sidewalk at all where people actually live (no benches, but more shade). It's a crappy time for a pedestrian either way and it's no surprise that most people don't want to make use of either option. However, I've found that on a scooter it's actually not terrible. The big empty sidewalks aren't so miserable because you get a breeze, and on the back-roads your scooter keeps up with cars better and has a light on it for visibility.
The issues with parking in bad places could be pretty easily solved with a some infrastructure for racks and geofencing to ensure riders end up there. The helmet issue can be changed by making helmets more portable and widely available. I bought a helmet for myself and my husband just to use the scooters. It's slightly inconvenient, but not a big deal. I can buckle it to my backpack. I'd prefer something that could fold up, or maybe a sharing model (leave a helmet / take a helmet at stations with scooters), but again I think that's something we can solve with regulation rather than outright banning. One thing I've wondered is if scooter companies could install a little camera facing the rider (or require you to take a pic with your phone camera) to verify a helmet is on before starting the ride using ML (like the "hotdog, not hotdog" joke app from the tv show "Silicon Valley").