I seem to be becoming one of those annoying free and open source software advocates since I installed Linux on my old MacBook Air a couple of years ago, but please let me offer a few points here:
First, if you don't want to buy new hardware, Linux gives you the option to install an up-to-date (and therefore much more secure) operating system on your old hardware. I'm running elementary os (not the most lightweight distribution) on a computer from 2014 with only 4GB of RAM, and it runs reasonably well. Not lightning fast, but fast enough that it's still pleasant to use.
Second, if you're not interested in subscription-based software, I think your best route is free/open source software. I think basically all commercial/propriety software is moving towards subscription models.
I use ART (a fork of RawTherapee), Filmulator, GIMP (rarely), and a few other FOSS apps for editing on my Linux box. I have not tried scanning or printing with this machine, so I can't really comment on that, although I understand there is FOSS available that does this well.
Here's a site with a lot of useful information about FOSS photography software:
PIXLS.US - Free/Open Source Photography.
Just a few points to consider. And please forgive me for being one of
those people.