Well, yes and no. I'm precluded from installing new Firefox via apt-get because my Ubuntu version fell off active support. Running a dist-upgrade is risky, and I don't feel like doing it until I know I have a spare free day to fix everything in case of a problem. A Firefox PPA would be a nice thing to use instead, for now.
If Firefox offered a .deb for $OS on their homepage, and Grandma attempts to install it while running $OTHEROS, then likely she will either 1) fail or 2) break her system. That's a worse user experience than a .tar.gz.
Asking Firefox to maintain packages for every outdated Debian-based distro is unreasonable. Nice to have, yes, but unreasonable to ask.
