Why is refinance shopping easier than purchase-loan shopping?

Future-Proof: Navigate Threats, Seize Opportunities at ICNY 2018 | Jan 22-26 at the Marriott Marquis, Times Square, New York

"I have heard that it is easier to shop for a refinance than for a purchase mortgage, but I'm not completely sure why...?" Borrowers purchasing a house are faced with a closing date on which they must provide funding to complete the purchase. This means that at some point in the process there is not enough time for the purchaser to back out of a deal and start anew with another loan provider. Once past that point, they are at the mercy of the loan provider. Purchasers who haven't locked the price of the loan by that time are particularly vulnerable. The loan provider promises to lock "at the market price" on the day the purchaser elects to lock, but the market price is what the loan provider says it is. If he cheats, too bad, the borrower is stuck. Even if the purchaser has locked, only the rate and points are covered. (Points are an upfront charge expressed as a percent of the loan). Neither lender fees expressed in dollars nor third-party settlement charges are covered by locks, ...