Pay a wage which is high enough to attract the talent that you need and which still leaves the company with a profit at the end. If there's a wide range that satisfies both of these conditions (and in markets with minimum wages, is legal to pay), then choose to offer a pay rate that best balances getting/keeping the talent you want vs the profitability.
If someone else can do my same job as effectively as me for half the rate, I'd expect my company to switch, just the same way as I'd happily take a 1/2 off coupon on the purchase of my next car, house, computer, or even groceries.