Only a very small but vocal minority of users disable JavaScript, as it's not a default setting in any of the web browsers with a market share higher than the rounding error.

In a lot of cases, designing a no-JS website disadvantages both the service provider and the users:

- the service provider has to support a higher load to render the page and process the data on the server,

- the user has to endure longer processing times for their data, since their request necessitates a round trip from/to the server adding additional latency.

For example, let's think of an image processing web app. All of this can be done on the client side (and this gives the user a higher sense of privacy since their data doesn't need to reach the server). It's much faster there, reduces the server load - allowing the service to be used by more people at once.

And there is no value in appeasing the no-JS minority, since either maintaining a no-JS version of the app in parallel, or building the entire app without JS, outweighs the potential ROI from the <1% of users[1].

If you disable JavaScript because of tracking and ads:

- browser extensions exist to only prevent tracking JS from running without affecting the websites,

- you can still be tracked server-side.

[1] https://gds.blog.gov.uk/2013/10/21/how-many-people-are-missi... - 0.2% of users of the UK online government services had JavaScript disabled. Based on the research I can find online, most of the no-JS users are using TOR, which isn't a terribly profitable demographic for commercial websites.