The majority of all tourists (B1/2) in the US come from countries with either visa-free access or sub 5% visa overstay rates [0]
And plenty of poor countries with Sub-Saharan developmental indicators like Pakistan, Cambodia, and Nepal don't have elevated B1/2 visa overstay rates compared to other countries, so if some countries with similar developmental indicators are seeing elevated abuse of the B1/2 program, then it should be cracked down on.