It's true that offering only the bare minimum of customer service is likely to increase profits in the short term. You could get away with doing the bare minimum, and, as long as you cover the basics, you won't have too many disgruntled customers complaining about your company. However, it's also likely that the customers who are forced to deal with that subpar customer service will probably not return to buy more from your business. They also won't be recommending you to their friends anytime soon.
Contrast that with a situation where they received a hugely positive impression of your customer service - maybe you went above and beyond their expectations, taking every step necessary to guarantee their satisfaction. In that situation they're definitely more likely to become return customers, coming back to buy more from you, time and time again. Most likely they'll also recommend your company to everyone who'll listen, and, in the end, you may receive a handful of loyal customers just from one perfectly-handled customer service situation.
As you can see, offering great customer service is likely to lead to increased profits over the long term, even if it costs a bit more upfront (and requires a bit more effort to pinpoint what works and what doesn't). This is a tradeoff that most businesses should be more than willing to make. What good does it do to make a few extra bucks today if your business isn't going to be here tomorrow?
The sad thing is: many businesses fail to consider this, and, as customers, we're often forced to deal with poor customer service from a variety of companies. The main offenders are usually large corporations who care more about next quarter's profits than their customers, but even some smaller companies fall victim to this mentality. Don't be one of them!