If customers do have these wide zones of tolerance for service, is it more difficult for firms with superior service to earn customer loyalty? Would superior service firms be better off attempting to narrow customers' tolerance zones to reduce the competitive appeal of mediocre providers?

Answer yes or no and why?

Source: Zeithaml, Bitner, and Gremler (2018), Services Marketing: Integrating Customer Focus Across the Firm (7th edition)

Wirtz and Lovelock (2016), Services Marketing: People, Technology, Strategy (8th edition)