It is a smart decision and a point where many companies fail. Excel works perfectly as it is, it is a product that sells well, there is no reason to change it.

It is a smart decision and a point where many companies fail. Excel works perfectly as it is, it is a product that sells well, there is no reason to change it. They modernize it from time to time, but they follow what may be the most important thing in production: if it ain't broke, don't fix it. Internet Explorer? It was already broken to begin with. Edge? No one wants it. .Net? Made to compete against Java, now facing competition from browser engines. These products have room for improvement, they need to be worked on. Excel just needs to keep being Excel.