I think older netbooks such as the 700 series could find a new use either as IoT or VoIP terminals and other non demanding tasks, by fitting them with just the bare minimum OS to run a single full screen application. Not that different from the LibreElec distribution whose motto is "just enough OS for Kodi".

Example: a 701 paired with an external good quality audio card plus Jaaa [1] might become a small useful standalone instrument for audio alignment (generator + spectrum analyzer).

[1] http://kokkinizita.linuxaudio.org/linuxaudio/

Jaaa is at about 75% of the page among lots of other interesting software.