Follow-up: I made a bz for it https://bugzilla.redhat.com/show_bug.cgi?id=1466993 and was promptly informed it's an upstream WONTFIX. See: https://bugzilla.gnome.org/show_bug.cgi?id=747046
So the GNOME guys in all their wisdom decided utmp wasn't important and proceeded to rip out all the relevant code:
"pty-helper removal is a nice win: 22 files changed, 22 insertions(+), 2944 deletions(-)"
Now I see what is wrong with "the kids these days", mainly the GNOME and systemd clowns. Their idea of a great "win" is to rip out 3000 lines of code that destroys agreed upon conventions? I wonder how many other things broke because of their destructive fervor.
So write to a pts is broken. But it's also broken to just "write trevor", unless you have at least one xterm open, then the xterm gets the message but not the g-t's.
For fun I tried wall. This is even worse. With only g-t's open the wall gives no error, appears to proceed, but produces no output on ANY g-t! WTF? At least write tells you it ain't going to work. So much for admins telling their users a reboot is imminent with wall.
Fun MUUG exercise: can anyone think of other standard tools that would be broken by this? I'll test them out and add them to the bug.
Expert MUUG exercise: can anyone think of a workaround I can use to write to a specific pts without using the "write" command? I'd still like to get this to work as a script I wrote depends on it.
Bonus exercise: can anyone recommend a terminal I should use instead of g-t. Seems every year I run into another g-t "XXX deletions, nice win!" problem. Absolute requirements: must be able to CTL-click (or something-click) urls to open them in a browser; must have either sane or user-configurable double-click-select characters; configurable long scrollback buffer. Gravy g-t has I can live without if I must: rewraps long lines when window is resized. Probably more things I can't immediately think of but use every day :-)
Oh ya, and xterm is very weird (unforgiving) in where you have to click to drag to select text, compared to g-t at least. But that I could live with, I guess.
Thanks!