Depends on your living situation. For most in the developed world there is very little that is worth the effort to salvage. There are a few exceptions, mostly driven by collector or fad markets. And even in the developed world many people don't have unlimited hobby budgets so salvaged components as an avoided cost can make sense. But there is no way to make a decent living selling them.
On the other hand, in undeveloped countries where there few environmental or safety restrictions and labor is cheap there are fairly substantial salvage operations. Buying from these operations is risky for those with first world standards because they have neither the equipment or the profit margin to do much to evaluate those salvaged components, but can provide access to otherwise unavailable parts.