As we study companies who have been around for a while, we see how important word of mouth advertising is for them.
This company in specific has been around for 40 years and most likely has been in the same location.
I would bet when they first were getting started, they really had to hustle with their marketing.
When you are starting a new business, it can take years for word of mouth advertising to pick up enough to fuel the amount of new customers your business needs. Don't worry about this though, just keep working your marketing. Keep getting the word out. That is part of the challenge of going from a start up to an established business.