What's old is new again. Microsoft introduced the "Office Startup Assistant" or "Office Startup Application" (osa.exe) in Office 97, it sat in the system tray and loaded the main office DLLs at startup: https://web.archive.org/web/20041214010329/http://support.mi... OpenOffice.org (predecessor of LibreOffice) copied this feature, which they called "QuickStarter", I don't know exactly when, but no later than 2003: htt…
Notably, a solution to the current issues with modern office is to use a copy of Office 97.
20+ page XLS uses ~7MB and loads effectively instantly (on a frankly horribly performing laptop that can usually barely run demos on HN)