Core GNU components (flex, libtool) in dismaintenance

In some way or another, most of us probably use software built in C with autotools and possibly containing flex/bison parsers. Just straight up GNU coreutils (`ls`!) needs at least the former.

All the more alarming that 2 core ecosystem components have fallen into "dismaintenance":

- Flex [https://github.com/westes/flex] - activity ebbed to almost zero around early 2018; year-old PRs piling up

- Libtool [https://savannah.gnu.org/projects/libtool/] - last release in 2015, sparse commit activity by a lone RedHat person

How could it come to these, and what can we do to address this? And what else might be falling into dismaintenance? (I only noticed these two because I tried submitting patches!)

(For libtool, yes, there are much better build systems nowadays, but it's still in use -automatically pulled in by autoconf/automake- by a huge number of packages; new build systems don't help, but maybe the libtool dependency can be surgically removed from autoconf/automake?)