A generic hardware and software platform for vehicle rentals could scale to support technically any kind of vehicle that supports personal mobility and uses some layer of physical security and authorization to operate.

It could be a reality that speedboats and other exotic forms of personal mobility is available for everyone to explore.

As long as the solution is based in cryptographic security that guarantees authenticity of vendors and costumers and manages authorization reliably there is no to practical limit where a rental platform can grow.