How high can you go on voltage?

I agree. Same as the heli scene. A year ago 15S ESCs were a dream. Now it's a reality with the Power Jazz. A few years ago ESCs couldn't run outrunners. Now it is very much mainstream.

What really needs to happen is car makers need to start putting out 1:8 electrics. So long as custom conversions remain the only route to 1:8 electric it will stay niche for a long time. Same story with the heli scene. A year ago there were very few larger than 30 size electric kits available, yet the conversion scene was very much happening - now there are more than 5 out of the box large electrics that are very affordable.

In a few more years nitro will be a niche market. :D