https://en.wikipedia.org/wiki/Trailblazer_Project
https://en.wikipedia.org/wiki/XKeyscore
The first one existed from the 90s. The second was built in response to 9-11, removing privacy protections early 2000s. The third is an interface for searching. As far as I know no one tried to deny XKeyscore exists, then or now.
Snowden built none of these. His document retrieval system allowed him to find out that the programs above were not following the law.
A wiki is a summary, of the available evidence, but from what I've seen, I'm not 100% confident the systems were active and deployed to the claimed maturity level.
I highly recommend the documentary "The United States of Secrets" by PBS Frontline, it digs into this time period and government motivations after 9/11. Usually free on Kanopy.
It's just as likely that XKeyscore was a strategic public relations effort to intimidate the enemy .
Believe here that all the tech was available by y2k and security was even worse than now. Just needed the funding and a willingness to break the law, which the govt had in abundance after 2001.