The reality is that anything more than 2 points to make up on 4th is hard to make up in the 8s (especially if points difference means we need to get more than 2 points).
When you look at the top 8s if everyone plays to form you've got 2 really tough games vs the top 2, and 3 really winnable games against 6-8. The same is true for both 4th and 5th placed teams. If you assume we both get the same sort of results (win 3 lose 2) of those, that only leaves two games to actually make up the gap (and you'd have to beat the team in 4th head to head to stand a chance). It would be a different kettle of fish if the lower end of the top 8s were actually competitive, but we've basically seen every year two or three teams just making up the numbers and barely competing.
I'm not saying its not possible to make up an even bigger gap than 2 points, but unless we're flying to the extent we can (and do) beat anyone, we really shouldn't underestimate how hard it is. In the three years we've had this system only one side - Sts last year - got into the top 4 from being outside during the regular season, and they were just one point behind Salford, who had probably overachieved to get there and imploded in the 8s.