Despite not sounding personal, I support the personal touch. Almost all of them will buy shortly. They are customers and treat it as such, but many are too busy taking quantity ups.
Back in baseball practice, we were told quality over quantity. That is mostly true today. There are exceptions, but I will focus on the parts that are quality over quantity.
Every customer that walks in is a quality up, but do we treat it as such? We must. Ask yourself this and rethink what you do. Otherwise, they are wasting their own time.
Beyond selling to serve, slow down and take the time to contact these customers, but how are they different? I will treat them the same for the most part, with some adjustments.