Hi folks
If you don't want all that advertising -- either stick to Horse Racing or Linux !!! -- These companies like Ms do at least provide loads of jobs, and also provide reasonably safe investment platforms which many people benefit from as they retire in the form of pension funds etc etc.
Any business needs a certain amount of "Selling / Pitching" and seed money to operate -- even one man "bands" if they want to sell anything have to make themselves and the product known.
personally I haven't found W10 itself riddled with Ads -- maybe some of the 3rd party software is - but you don't have to install it and you can totally ignore / delete any of those hideous modern UWL Mobile phone type apps too.
Things like Google are far more pernicious in their use of personal data gleaned from people's use of computers -- and that can be totally OS independent as google is used on phones, tablets, macs, windows and Linux platforms anyway.
There are things wrong with W10 but so do other OS'es have flaws as well. On the whole W10 works perfectly OK.
Cheers
jimbo