Well if the majority of developers are mostly using web-based technologies such as JS, TS, HTML and CSS, and all you're doing is modifying the site and shuffling around elements + a11y addition, etc that is something an AI can do in seconds.

Seems indeed to be like Warehouse work, which is why Web developers will be the first to be affected by AI.

Doesn't matter if you are "senior" or "staff" in Web development. AI is already senior staff level in that.