Strouty,
I feel your pain and regognize myself in a lot of what you are saying. I have much less stuff, but my space is also a fraction of yours. The "stack overflow percent" is probably similar

And I did consider tossing EVERYTHING, quit playing a handyman and getting a condo.
I tried to get organized, tried to utilize everything, tried not to throw anything "valuable" away. I would hold on to stuff that had no value to me but for someone maybe sometime... As a result I got a "reputation" and people started to offer me hand-me-downs. This led to endless sorting operations and moving **** around. There were no empty space anywhere, so when I acquired something bigger than a box of screws, the whole operation fell apart, I had to spend hours re-organizing my **** and the result was I stuffed stuff deeper in the storage, more compact or piled it higher. Hardly ever tossed much away.
And, being a perfectionist, I spent time planning and figuring things out, sorting boxes of old screws and bolts by size, spending 20€ on bins to store 5€ worth of unnecessary ****. At some point there was a "click". I realized that instead of getting things done, I had spent a few years of my precious spare time and money trying to get my shop organized. I had some success but, for example, my motorcycle was waiting, un-rideable, for me to install a couple of new bushings for an entire summer.
So I started to get rid of stuff, and started to accept the fact that not all my screws and bolts were not perfectly organized. I am in the very beginning of this new path. We moved to another house and now my shop and storage space is different and much smaller, so that's another challenge. I am currently organizing my combined 11x18 shop and storage with the mind-set that it will not be perfect the first time around. Because no matter how hard you pre-think and ponder the organization, within a month after you think you're done, you are going to change something. So, rather than spending time wondering, I started to organize, accepting the fact that it may not be perfect. The first time around anyway
I list sellable stuff on a web marketplace as I come across it. I take a photo with my iPhone, later in the same evening I use the phone to list the stuff. Easy because the photo is there already and it is easy to attach. The photo album also works as a reminder of what I am supposed to list. I am a procrastinator by nature so I really have to fight the temtpation of leaving the listing to tomorrow or next month. I put a low price on everything, and have sold a lot. The web marketplace I use has the ad up for 2 or 3 weeks, after that I get a notice that it will be deleted unless I click a button. I don't click the button, I just either recycle, toss or donate that item and get done with it.
Sorry for the long and winding post.
I suggest that you too start accepting "less than perfect" result, stop buying and rearranging bins and cabinets and organizers and start to roughly sort your stuff instead. Anything not directly connected to your mast business or items you have not needed within a couple of years should go. Easier said than done, I know. Maybe you could arrange the extra stuff on pallets, and have them auctioned? You ended up with most of that stuff exactly the same way. It probably was someone else's miscellanea that they got tired of tripping over. Don't worry if you don't get a good price, because just now the value of the stuff is negative and anything you get for it is positive. If nobody buys it in the auction, scrap or donate it. The main thing is that you don't need to deal with it any more.
Keep the business stuff, but store large stuff somewhere else, not in the shop. If necessary, sacrifice some shop area for storage of large items, but keep the storage as a separate area. You have a lot of your cabinets etc on wheels, that's good, it's easy to set up the work area for each job. You already have a store room for small stuff, that's good too, keep it there, don't bring more bins or cabinets to the work area.
You'll get there, just keep going