I've been involved with residential and small commercial real estate for over 35 years. While I agree that most shops, oversize garages, pools, expansive landscaping like fire pits, pergolas, etc, etc. don't add a lot of value dollar wise quite often sellers could recoup more of the $$ spent on said "over-improvements" if the seller would spend more time cleaning and freshening up the shop/garage, etc.
Over the years I've seen properties sell well below value due to the garage/shop/attic/basement being crammed full of projects, stuff and junk-even though the house itself had been nicely remodeled, was in move-in condition, showed like it was ready for HGTV and properly priced. The garage/shop/attic/basement may be organized to the owners but most potential buyers can't overlook the mess and only think about the time, effort and expense to clean it up and make it useful. To reach the highest potential sales price a seller with a clean (not filled too brim), freshly painted with a little of attractive landscaping garage/hop, etc. will have a huge advantage over the average Joe's garage shop with a partially dismantled project vehicle, its parts hanging everywhere, and greasy containers and boxes overflowing. Don't forget he drywall buckets half filled with used oil and antifreeze
These over-improvements, if they are clean, in. good condition and have an attractive appearance will usually recoup a bit more (not necessarily a huge amount) at sale time and if properly priced can result in shorter time on market. Unfortunately most of us as sellers (and I include myself at times) are so used to overlooking our not so organized, not so spotless and not very attractive garage/shop that we don't think about how it would look to potential buyers.
An old advertising adage was "You sell the sizzle, not the steak". 90% of potential home buyers have little if any ability to see past what is currently there in front of them. Also 90% plus of buyers want the property to be in clean, move-in condition and not needing any fix-up or repairs. Few buyers anymore have the knowledge, skill or desirel to be DYI'ers anymore and they don't have family members or friends to teach/assist them. My guess is that the majority of GJ members DO NOT fall in that 90% catagory. I know I don't.
While it was a lot of work, I enjoyed most of clearing out an estate mill house in WNC we purchased a few years ago (it was a good deal even with a couple of hundred hours of cleaning). Digging thru the 50 years of accumulated stuff took many days and yielded over 4 tons of scrap metal and untold trash cans full of **** and garbage. But I also got a large batch of older hand and power tools, compressor, old car bits and pieces, and other cool stuff, even a '47 CJ-2A project. Just clearing out the property and yard increased the value by 20%. Once we replaced the monitor kerosene heater with a modern HVAC (with new electric service/upgrade that cost almost as much s the complete HVAC system!), did an inexpensive kitchen make-over (panelling replaced with drywall, new cabinets, counters, appliance, flooring, lights, etc. ran about 5K) and fresh interior paint it was worth over 75% more than our purchase price. While it still could use more work it's clean and livable (we use it as a weekend getaway and until Covid, we used it 15-20 weekends/year). Last fall, we had an unsolicited cash offer well over 2 times what we've put into it over the 6 years we've owned it-not a bad return!
We plan to move out of our current home in a few years so I've already started clearing out some of the excess parts, junk, etc.out of the attic (down by @ 6o%) and garage (down by @ 15-20%). Garage is 24x34 with @11.5' ceiling, so while it's not huge I've managed with a little effort to overfill it. I've also done some landscaping and planting (and will be doing more this spring) to give trees, shrubs, ground covers, etc. a chance to mature and fill out a bit. Before it goes on the market I'll have the garage pretty much cleared out (currently has pallet racking down one side and shelving across the back, several cabinets on rollers, workbenches) culled down to just 1-2 shelves, 1-2 cabinets, 1-2 tool boxes and a one workbench (cleared top-no stuff piled on it). It'll be freshly painted in and out, all lights will be working, floored power washed (possibly coated floor too since I don't know how well the floor will cleanup). All the projects and related parts will have been relocated (even IF I have to pay for off-site storage) and only a nice vehicle(s) will be parked there-no beaters in sight!
If you're thinking of selling 2-3 years from now, now is the time to start planning and preparing so you're not spending every spare minute dealing with it at the last moment.