I'd agree the efforts have not cut off that kind of business 100% but they've been effective in reducing the amount of conflict business, as well as reducing their profitability making them do more work to put the items on the market.
Conflict diamonds and gold are a different market framework than electronics components though - those items in particular have much different and arguably more varied sales avenues that make them more difficult to stop. Electronics components have an inherent complex testing quality and fewer channels for markets to move through so should be easier to control on a regulatory basis.