The fact that the word "excel" is nowdays synonymous with "spreadsheet software" is exactly the reason why we should NOT teach kids how to use MS Excel.
There are many free implementations of spreadsheet software. Kids can get even more experience using different kinds of software, teaching them ways in which software can differ while still being able to do the same things. Ironically, this would probably make kids more skilled with MS Excel, if they were ever forced to use it.
There's no reason to teach kids MS Excel in particular, unless you think memorizing positions of buttons is a useful skill in the real world.
math skills are transferable and universal. Teaching excel specific functions is like teaching to drive by using one single car model. And cars have almost identical interfaces. So one should tech concepts not functions.
imagine a market for 3D animation software - Maya, 4D studio, etc. like 4 companies.
If 100% of a country's schools start teaching software from company A, thats a massive subsidy - basically 100% of the population will know how to use their software and prefer it to their competitors. Businesses will buy that software because everyone already knows it. You are massively distorting free market.
With a conoany thats already a monopoly, thats doubly unfair.
I would argue it is far more helpful for 80%+ of kids to learn excel than to learn advanced maths.