Look at how fast Excel loads. Compare to modern high-end PC with it's latest version.
Office really chugged on the PCs of the time though. We can debate whether modern Excel actually delivers enough more value than historical Excel to justify being as more resource-hungry, thus slower to load, as it is. But historical Excel appears fast on modern hardware, even in emulation, because the CPU, RAM, and permanent storage have had 30 years to evolve since it was released. Contemporary 386s and 486s would not have been that snappy.
I came to write exactly this comment.
The thing runs instantly. And that's in a VM in Javascript.