Ones who want to stay hidden, will. Most of plebs won't.

A small group of people making noise to try and obfuscate themselves will just draw attention, won't they?

True, unless they use noise which is already present online to carry information, for example by applying steganography to spam.

If only the people who want to stay hidden use noisetech, they stick out like a flame in a dark room and will immediately attract personalized surveillance (and maybe even retaliation merely for using it). It doesn't work unless everybody is on board.

Starting with the "classic" techno-libertarian slaves who each claimed "I am spartacus"