Oh hang on, I know. The locoscript word processor booted in seconds, on 1980s hardware - just like everything else back then, in fact. Who'd have thought load times would go backwards after 40 years of Moore's law?
Also, Locoscript 1.00 really was anything but fast: saving a document over about 20kb to floppy could easily take a minute or two, and if it exceeded the free disk space the WP would crash hard with a corrupted screen buffer ...!
(Source: a PCW8256 was my first real computer, back in the day.)
My understanding was that although you would flip the disk to boot in to Locoscript, at root it was running on CP/M, albeit with the CCP replaced by Locoscript. It would seem odd for them to re-engineer CP/M functionality - though given that CP/M was rather incomplete as an OS, it would naturally have to touch some bare metal. I never really investigate to check that belief. Is there a reason that you think that it didn't use CP/M?
"Wirth's law is an adage on computer performance which states that software is getting slower more rapidly than hardware is becoming faster. ...Niklaus Wirth...discussed it in his 1995 article "A Plea for Lean Software". ...Wirth attributed the saying to Martin Reiser, who [in 1991] wrote: "The hope is that the progress in hardware will cure all software ills. However, a critical observer may observe that software manages to outgrow hardware in size and sluggishness." Other observers had noted this for some time before; indeed, the trend was becoming obvious as early as 1987."
I used to use WordStar on a CP/M machine well into the 1990s because at most its 5.25" disks kept you waiting for two or three seconds.
I had a lot of fun working my way through the infocom archive, especially playing the Hitchhikers guide, and writing my own simple four-room adventure game.
CP/M is basically dead, but there are enough retro-fans such as myself that it'll probably still live on for another fifty years.
Decades later you still need to pull stuff off those old floppies occasionally.