The late, great TRS-80

The built-in display was a 1-line 32 character alphanumeric unit. Hardly a 'calculator display'. In general you linked up the 9866 printer if you wanted a larger 'display' for things like program listings. If you wanted graphives 9and were rich!), you eitehr linked up a plotter -- there was a pltoter ROM add-on to BASIC that added useful statements to drive the plotter -- or you got the HPIB interface, an HP1350 'graphics translator' (vector display generator) and an HP1311 monitor. I am wondering why you consider the dispaly to be an important part of the machine, though. This thing was not designed for games, after all. It was designed for scientific data processing, data logging, control, and the like. For which yuo probably don't need more than a 1-line display.