Top salespeople are often the veterans. They have deep relationships, and when there is an RFP (request for proposal) or a big contract up for bid, they know just how to zero in on that transaction and bring home the biggest share of the business.
The prospect has already decided they are going to spend that money for your product or industry. It's the "money on the table" or the low hanging fruit, and the issue was always about beating the competition.
Transactional business is critical to secure, and the big wins take hard work. But those successes can blind even the best sales reps from rocking the boat enough to look for more opportunities.