I usually figure that insurance on average is a losing game for the buyer, because the seller has to pay business expenses, answer to shareholders if a public company, and in general hedge against excessive losses.
So I avoid buying insurance unless it is something I can't afford the downside loss on, or if it is legally required. I also generally go for high deductibles. So I carry health insurance with high deductibles, home insurance with like a $5K deductible, and liability insurance on my car only - no collision/comp. I don't carry life insurance, LTC insurance, or disability insurance.
So in your case, yeah, on average you're going to lose money by buying insurance on your stuff. The real question to ask is this: supposing someone stole all your stuff. Could you manage to find a way to replace it or otherwise go on with life without the assistance of the insurance company? If so, I would suggest self insuring, meaning you keep that risk on your own shoulders rather than paying the insurance company to take it for you.