Comment by fulafel

Yep, and those printers are proprietary and mutually incompatible, and there are buggy mutually incompatible serial drivers on all the platforms which results in unique code paths and debugging & workarounds for app breaking bugs for each (platform, printer brand, printer model year) tuple combo.

(That was idealized - actually there may be ~5 alternative driver APIs even on a single platform each with its own strengths)