In what other similar user-facing system would that be the case? There is an impedance mismatch just in the fact that a UI is much different from code itself. There is a mismatch between what your parents can learn to use (UI) vs. what computers can understand (code). Most other UI projects are compiled (native apps), and they don’t even need to care about sending that final executable over the wire very quickly, or even other web optimizations a bundler might do like code splitting.

These systems become complex because the web is a much different deploy target than, say, iOS.