Yes, it's certainly not impossible to display white backgrounds well on CRTs in general (consider upmarket late-'90s CRT monitors in particular, still overall d

Yes, it's certainly not impossible to display white backgrounds well on CRTs in general (consider upmarket late-'90s CRT monitors in particular, still overall decent displays by modern standards) but it wasn't to be taken for granted on early-'80s CRTs. White-background display conventions more or less came in with the Engelbart/PARC GUI and IIRC (I think Levy's Insanely Great or https://folklore.org https://folklore.org discusses this?) Apple put a lot of effort into making the original Mac's (and I assume Lisa's) monochrome display pleasant to use in that manner.