There's a lot that WordPerfect got right in document management, esp. for large files, as well as innovations in formatting capabilities and sophistication. Sure, it's not latex, but it nicely captured the space between "desktop publishing" and the dinky small document tools so prevalent before it (primarily Wordstar variants).

Shifts in ownership and strategy (Windows and GUIs in general threw it for a loop) really knocked the wind out of them, but for a time, WP was both the cutting edge and the go-to tool for many writers before the MS Office hegemony arose.