Whether B2C or B2B, all businesses know that quality leads are the backbone of their business. One will have all the organic as well as paid ad traffic to their website but unless you attract "willing to buy" audience, it will be a hard time for your cash flow..
Only Experts know how things work. Generally when a website is designed and hosted, the first and sometimes the only expectation it is suppose to fulfill is - Generate Leads. Pressuring a website devleloper to get you the leads won't help as he won't be able to do it.