I worked my way through the package difference between basic and minimal, and found out that if I include the bc package everything works as expected. Now I can reboot and the power model gets set correctly from the config file. Not sure exactly how the bc package specifically interacts with nvpmodel though…
$ apt show bc
Package: bc
Version: 1.07.1-2build1
Priority: optional
Section: math
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Ryan Kavanagh <rak@debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 223 kB
Depends: libc6 (>= 2.17), libreadline8 (>= 6.0)
Homepage: http://ftp.gnu.org/gnu/bc/
Task: server, print-server, ubuntu-desktop-minimal, ubuntu-desktop, cloud-image, kubuntu-desktop, xubuntu-core, xubuntu-desktop, lubuntu-desktop, ubuntustudio-desktop-core, ubuntustudio-desktop, ubuntukylin-desktop, ubuntu-mate-core, ubuntu-mate-desktop, ubuntu-budgie-desktop
$ nvpmodel -q --verbose
NVPM VERB: Config file: /etc/nvpmodel.conf
NVPM VERB: parsing done for /etc/nvpmodel.conf
NVPM VERB: Current mode: NV Power Mode: MAXN
0
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