As someone who was in the industry in the 90s and 00s, and saw just how many man-hours were wasted in dealing with problems caused by MS's buggy and insecure software, I don't really count this as "improving the world and people's lives". Even at the time, there were far better alternatives available; they just didn't have the same marketing or lock-in advantages.

I'll grant you the stuff about FB, Amazon, and Google though, and maybe Apple with their iPhone.

>The problem is, once those goals were accomplished, there was a still a need to keep revenue and profits rising. Which always seems to end up with selling ads at some point.

Yep, this is the problem: unsustainability. These companies should have been able to shift into a "utility provider" type status where they don't really grow much (except from expanding population, or new untapped global markets), where they can simply provide a fairly constant service and have a regular revenue stream.