Hardware-wise that processor architecture is obsolete and a dead-end and is probably why they haven't upgraded the hardware. They would need to, basically, rewrite all the software from scratch.
I suspect that somebody with a arduino or similar thing could create a board to interface with ebike components and ultimately end up with something superior, but it would require a tremendous amount of work and testing.
Despite all that it continues to work and they have improved the firmware and introduced more features. Like the "virtual electronic freewheeling" feature, which provides enough power to just overcome the cogging forces of hub motors. The nature and requirements for ebike haven't changed much since years ago. So functionality-wise it's not obsolete in the least.
Open source controllers like Vsec or the KT firmware probably have more potential then CAv3, but in terms of something that "just works" (in conjunction with a CA-ready controller) I think it offers tremendous value and is really a significant upgrade over normal kits and most affordable pre-built ebikes out there.