No dynamic linking locks you out of Clang+LLVM (mostly: static clang isn't an officially supported configuration, but it can probably be forced to exist. I haven't properly looked into it yet.), Firefox, Chromium, QtWebEngine, (so no alt browsers, either), and probably a lot more. Statically linking every single package out there requires a lot of patches to build systems to get them to properly do it. Many build systems don't respect LDFLAGS and CFLAGS, or respect one or the other, or only partially respect them, causing a great deal of annoyance if you have a nonstandard desired result, such as fully static builds.
Sounds good, doesn't it? This means that efforts to produce a fully static distribution would imply a sweeping wave of fixes across a wide range of packages and build systems!
"[Ultrix] never supported shared libraries or dynamically linked executables."
There's still a long way to go. The elephant in the room, prudently sidestepped by the hyperbola community, is the removal of dynamic linking. Now that would be a great, but difficult, brave choice. Most of the other removals (except the removal of dbus, which is mind-boggingly awesome) are fairly isolated stuff.
Fortunately, they are steadily taking steps in the right direction!