Nothing on the web is ever removed
On deprecation as a social process rather than a technical one, and why the pile only grows.
Deprecation on the web means something different to deprecation anywhere else. In most systems it is a schedule: marked in one release, warned about in the next, gone in the one after. On the web it is a mood. Something is deprecated when the people writing the specification would prefer you stopped, and that is the entire mechanism.
The pile only grows
It is worth being concrete about how little actually leaves.
| Feature | Deprecated | Still works today |
|---|---|---|
<center> |
1998 | Yes |
document.write |
Discouraged for ~15 years | Yes |
| Quirks mode | Superseded by standards mode | Yes |
<marquee> |
Never standardised at all | Yes |
| Third-party cookies | Announced dead repeatedly | Complicated |
Only the last row is genuinely contested, and it is contested because it is the only one where somebody with commercial leverage wanted it gone. That is the tell. Removal is not a technical capability the browsers lack; it is a political one they rarely have.
Why the constraint is real
The reason is the same one it has always been: nobody can redeploy the web. There is no version of the corpus that gets recompiled. A page written in 1997 by someone who has since died is still served, still requested, and a browser that breaks it has broken the web rather than fixed it.
The install base is not the browsers. The install base is every document ever published, and it does not accept patches.
This is a genuinely unusual engineering constraint and it deserves more respect than it gets. Most of the platform’s apparent incoherence is the cost of it, paid honestly.
Where it actually bites
The cost is not the dead features — those are inert and cheap. It is that every new feature must be designed to coexist with the entire history, and that shows up as syntax nobody would choose fresh. Cascade layers exist in the shape they do because they had to slot into a cascade that could not change underneath them.
That is not a compromise imposed on good design. It is the design problem, and the specifications that ignore it are the ones that never ship.