I did earn some bread with vba as well, and always advocate for efficiency, but I just opened a 12MB xlsx file in LO, and it took a couple of seconds on a 2024 thinkpad.

As far as I remember, my Win 3.11 machine (a 486 DX with 4MB RAM and 30MB HDD) wouldn't be able to store or open such a file, let alone recognize the extension. Also, it would call the file 2026022~.XL~ or something. And it took more than a couple of seconds to load office programs for sure. It would take well over a minute to load a book from a 1.44MB floppy.

Anyway, software and computers have come a long way and I'm grateful for it.