Less than 2% of all web users have javascript turned off. Some say it's less than 1% and it's mostly people who understand the consequences of doing so.

Turning off the native component of anything always has consequences for those tinkering under the hood and the vast majority of those visiting that site don't tinker under the hood.

As the owner of a web dev company, I sometimes consider ignoring the "must work even without javascript" mantra. I haven't yet but there are times.