Let me put put it another way, that's just the start. You would effectively need the EU to operate a SaaS service and compete against MS. The money is hardly the issue, you can't just throw money at it or say the magic phrase "open source" it isn't for a lack of money that libreoffice is nowhere near excel for example, tech people would actually say it is pretty good without knowing how these apps are used.

It is the digital equivalent of replacing all cars of a certain make that everyone uses for critical business functions and replacing them with your own line of cars that will take a decade plus to even mature after you spent a ton of money and an army of devs and dev-support/mgrs.