You do realize that that was the big problem with IE security in those days: ActiveX. You literally could embed an Excel file in your HTML page.
You could embed any native code and it would just be a small yes/no dialog to download and run it.
Imagine a world where instead of letting IE die, microsoft decided to add a <XLS> tag in the early 2000. The most used nocode database in the world directly in the browser. In 2000.