The interplay of place-to-place records and the 24 hour TTs is an interesting area. Road Records Association records were the province of professionals at one time, and depend on the right weather conditions.
24 Hour TTs are a purer test, but have been subject to improvement from bike design, nutrition and training. There are also lots of different 24's. We've got the 'World 24 Hour Champion' on here. That's an event promoted by the company that now owns RAAM. It's all a bit like the various boxing titles. With lots of room for fans to decide who is 'The Greatest'. There's no money in it though, so it has a bit more purity.
As Wheels of Fire hints, a lot is down to the team behind these rides, both on the road, and domestically. As a spectator, one has more contact with the team than the rider.