It is possible that the top scorers early are guys that haven't really set up their teams for the long run.
I don't know if this is the case in NRLF this year but in VSDT, the guy currently in 1st has 8 absolute bottom dollar guys on his bench that have played 1 game so far between them. The result is that while he has the absolute maximum amount of money tied up in his starting 17 as is possible now (and is scoring accordingly) he will not be in contention come the end of the season cause he simply won't be able to generate the cash required.