You said a "big reward has been on the table for years", which makes it sound one way, but as I recall Bobby offered his challenge only for a period of time, only intermittently during that period of time at his whim and convenience, and only to one person at a time at most, only at his personal invitation and approval, and only if they came to his location. Effectively, the majority of the time nobody was eligible for any high run prize from him at all, and the rest of the time only one person was eligible.
To be fair, having a prize available only part of the time, only to one person at a time even when it is available, only to people who are willing to travel to your location, and only to people who you personally invite and approve of, is way, way different than just having a prize available to anybody at any time the way you would make it sound when you say a "big reward has been on the table for years". But yes, one person had a chance to win a prize a small part of the time for a little while.