I think you need to define “bad deal” a little more. Insurance is money you’re basically throwing away if you never need to make a claim - and in a lot of cases you do hope you never need to make a claim. But that doesn’t necessarily make it a “bad deal”. If the items you’re risking are enough that you replacing them would be more likely to kill your hobby - insurance isn’t a bad deal, it enables you to have this hobby. Because if you leave your camera at home because you’re afraid of losing it or breaking it - well, you’re not actually getting much use out of it (in most cases).
The other thing is you can perhaps have more information about your situation and be pretty sure you’ll need to replace or repair something in a way that doesn’t necessarily widely apply or see insurance companies offering extremely low rates for some situations - perhaps something like loss leaders. An example might be some of the house insurance policies that have a rider for mechanical breakdowns, where the rider is a very low fee ($45 a year say). If you know it covers well pumps, and that you’ll need to replace your well pump in ~10 years, the cost isn’t going to exceed the cost of the well pump installation minus the deductible. I assume this sort of policy works because the company also sells a lot of these policies to people who don’t have wells.
The other nitpick I’ll have here is that unless you define “bad deal” as “not the cheapest option overall”, you’ll have way more reasons to discard this idea. For instance, in a lot of ways financing is a “bad deal” in that it costs more money, but might be a “great deal” because you can actually get a car you need to earn money to live with it, and you’d starve before you could save up thousands of dollars for a car.