LineageOS's problem is not volunteers.
It's that you need intimate and hardware-level knowledge of the device, with suitable drivers, complete functionality, access to secure bootloaders and boot partitions, several devices of each type to test with (okay, they may be able to help there), and lots of potentially-damaging experimentation to get to the point that you can *see* anything on the device, let alone make all the third-party components like cameras, etc. work properly.
LineageOS doesn't really fully support many models at all, and the ones it does are essentially random based on hardware support and software driver availability. Do you have a driver for an obscure, Samsung-phone-only part that only exists in one phone and provides, say, fingerprint reading via the secure enclave? No? I'm sure we could just ask Samsung for it...
LineageOS is a LOT of hard work. No way that even a commercial entity is going to be able to fund or help that in any significant fashion, especially not for even a handful of models going forward onto years-in-the-future OS which won't really work with you (Google aren't going to help out LineageOS any time soon, because then they'd lose control of Android).
It's like Coreboot and other things along that ilk. Complicated. Technical. Working in the dark. No support. Never fully supporting everything. Hindered by basic security. Able to trash the machine permanently at the first mistake. Undocumented.
Throwing a couple of old phones, and even funding a couple of people's salary to do it 40 hours a week, isn't going to make a dent in it.
I have a LineageOS phone. I did it to my S4 Mini, which has a great IR blaster, which I use to turn my gadgets on. That's it. The camera is unreliable, the Wifi isn't great, some of the features don't work at all, and it's 3 or 4 versions of LineageOS behind now, and even then it's "unofficial" LineageOS from a forum post that I didn't care if it worked or not as the phone was headed for the bin anyway. It's never been updated since.
Pretending that LineageOS is the solution to this is crazy. It's just a bunch of amateurs hitting on Android code trying to get it to load on devices without any support whatsoever. They are just as far behind on security updates and OS updates on many models as the official Android for that device, and take out your warranty etc. in the meantime.
There's no business interest there for a reason. They'd end up with a bunch of LineageOS'd phones that were still out of date and couldn't be updated, but where several features of the phone didn't work at all, and they'd be "responsible" because the base Android could have supported them - so when are you going to fix it?!