OMG Andy! Just read the entire thread. I've been busting a gut at your dilemma because its like looking in the mirror! I've been smiling with the involvement of your family and great grand kids. (What a treat). Sad to hear of your mother passing.

Laughing some more when you find stuff you haven't got a clue what it is! And cheering for you because you've made such amazing progress in a few weeks.

(P.S. Please don't check my thread as I've got the same hoarder gene - although it might not be quite as dominant as yours ... or else I haven't had as much time to work on it.)
It reminds me of the famous "To Do List":
To Do List:
1. Make a to do list.
2. Check off the first thing on the to do list.
3. Realize you've already accomplished 2 things!
4. Reward yourself with a nap (in progress)!
Anyway I love the progress you've made! It's an epic accomplishment!!!
I will share a short (philisophical) story... I used to have a neighbor that had the cleanest yard and house imaginable. His secret was to throw everything out! He would buy a broom to sweep his driveway, and it would be in the dumpster the next day. He'd buy a new bike. Old one is in the dumpster. New garbage can, new ... whatever. Old (whatever) is in the dumpster. Like you, I just don't understand that mentality!
Unfortunately, the stuff didn't stay in the dumpster. I rescued it. And I still have a lot of it. ... do you see where this is going? I've built shelves and sheds and places to store more of this "stuff that's too good to throw away". I no longer live next to that neighbor. I had to move a lot of the junk (good stuff) that he threw away.
I sometimes think back to the method to his madness and sometimes wonder if the cost of storing and building storage for "all that good stuff" isn't more expensive than just throwing it away and buying what you need when you need it?
Well I'm still not convinced which way is better but, just for good measure, last weekend I've been building more storage shelves

and started sorting through a lot of stuff I inherited from my dad after he passed away several years ago.
Your efforts are inspiring me to keep moving forward on my cleanup efforts!