It's called trust but verify. Without proof you're just talking shit and wasting everyone's time and effort. But you know that because you're disingenuous, not stupid, right?
At this point I don't think it will be, to be honest. And at this point they don't need one, their pretend assistant has the ability to record all the activity anyway
Microsoft does collect a lot of data. But storing every keystroke is first of all impractical, because it would take a lot of disk space to store every keystroke of every user, and secondly not very useful unless they also knew when, in which application, and in what context each key was pressed.
Think about it practically. Microsoft is not an advertising company, they make their money from enterprise software. Windows is installed on billions of computers. The infrastructure required to accept and process every single key pressed by every single windows user and turn it into something usable would be enormous. And for what? To make a few extra millions by selling it to some advertising company?
Microsoft is an advertising company just like Google, Meta, Amazon, and Apple. Bing search and Edge browser in Windows are a few ways ads are shown to users. Netflix is using Microsoft ads network for their platform to show to their subscribers. Companies pay a lot of money to get preferential suggestions/queries on their stores and search engines.
Microsoft generates over 10 billion US Dollars per year in revenue from their advertisement division. The revenue growth from their advertisement business is growing exponentially at around 10 percent every year.