To me it's the tech equivalent of painting yourself into a corner, sure it works at the moment but what are the hidden costs of sticking on a dead end technology? What's the upgrade path from a C64, a C128? What happens if a chip on the circuitboard fails, or the power supply? Can't exactly order a new one, they stopped making them over 30 years ago and the company has been defunct for basically the same amount of time.

I wish I could remember more details, but I remember years ago reading about a company that had a core product that depended on an old 286 era laptop with a special software/hardware combo for maintenance, and all I could think of was that a single accidental bump of a table was all it'd take to shut down that product for months until they could find the exact replacement.