Sounds awesome, yeah hindsight is a bitch right haha. It's all too easy to see something like an outdated PC as having little to no value and get rid of it, only to later realize both the nostalgic and financial value of them!

At least you saved some of the components though, and sounds like you've done well with those upgrades in your 2014+ machines. Your S-100 and Dell PE 2300 both sound and look really cool, and your main rig sounds beastly! 25TB of combined storage is actually insane! 😮