If windows, a software for which I pay money when I buy a laptop can have ads, I am pretty sure at some point Github will also have ads. Its very very tempting to leave free money on the table. Only time will tell (Even though you are the CEO).

Except it ain't free money. Especially when you have viable alternatives like BitBucket and GitLab that are able to operate just fine without ads (well, at least without ads for non-Atlassian products in the former case), the cost is people jumping ship, and git makes that easy to do.

Microsoft would only stand to gain (short or long term) if it's been engaging in its traditional EEE strategy this whole time and is ready to pull the trigger on that final E. Even if that's the case, I can't see any real benefit; it'd just be a middle finger to developers.

Y'know I wonder if there was some legal way to guarantee this promise? ToS's are often "we can change whenever we want, we make no promises".

But can you say Microsoft will not use private GitHub data to sell or run targetted ads outside of GitHub?