It is short-sighted to assume that 2x will be the limit of high-resolution images. If we're making browser developers add support for this, we might as well have it be at least somewhat future-proof.
Meaning of "1x" has changed from 72dpi to 100-130dpi over time.
It's not unreasonable to assume that same will happen with "2x" as screen densities gradually improve, and over time it will shift from 220dpi to 300dpi-400dpi (for desktop viewing distances).
Density doesn't need to improve indefinitely, it just needs to cross the "retina" threshold (which arguably 2x does already).
It's not unreasonable to assume that same will happen with "2x" as screen densities gradually improve, and over time it will shift from 220dpi to 300dpi-400dpi (for desktop viewing distances).
Density doesn't need to improve indefinitely, it just needs to cross the "retina" threshold (which arguably 2x does already).