memes

That's thinking of it way too much like an ideal one for one transaction. Insurance companies don't based their profits on how much the stuff costs to replace directly, they make money based on the cost of payouts compared to premiums. If they can get enough clients to pay the premiums, they could pay 10x costs and it would make exactly 0 difference to their bottom lines.

It's actually the reverse in many situations, insurance exists to help recoup costs in an emergency and if you have a policy that doesn't pay enough to recover from a loss then you are underinsured, and the only way to ensure that is to buy a policy where you're at least slightly over insured. That's why homeowners insurance is based on replacement cost, not on the cost when you bought it.

Business insurance admittedly is different, but to be fully covered, you are also getting replacement costs for things like stale product, depreciated equipment (which depreciates differently for insurance purposes than for taxes and accounting) and things like building and infrastructure which are at replacement costs vs purchased prices.

Basically insurance companies are less concerned with having to make absolutely sure everyone gets as screwed as possible on every individual payout, than they are making sure they're collecting premiums much faster than they are having to payout at all. Writing every policy so that no one 'ends up with a plus' is far less profitable than making sure they are selling policies that are useful. Of course they also want to pay out as little as possible, but that is not nearly as attainable as calculating the likelihood of risks and raising rates whenever possible.