All in all I find myself in agreement with the following exceptions or observation.
Project guns can be a good thing if brought with a true vision of the cost and value when complete. When I had 38 long guns you are more right about it than I care to admit. However, when I am reduced down to four guns plus one or two projects are valid. (I cannot decide if one of my double rifles is a project or simply a gun sale not yet made)
My rules for project guns are simple.
1. Understand you will be upside down when complete. This is a 95% probability.
2. The gun has to fit an actual need other than desire. I.E. You need one heavy waterfowl/clays SxS in your battery and this will be the only one you will own.
3. You pay cash for all work, no debts for either purchase or restoration
4. I look upon all gun ownership as rental ownership. I have made actual profit money on a gun deal a few times out over 50. All profits, the few I made, were made on the purchase price, not the sales price. They did not go up in actual value.
5. Never have more than one project gun at a time
These rules stated, I admit I did not always live by them until the last few years. I own one completed project gun and recently purchased a new project (matching 20 SLE to a 12 & 16 on hand). My pleasure from six SxS guns is greater now than when I had 38.
Lastly in respect from your comments in having too many hobbies, I cannot more agree.