They also got beat 49-30 by Cronulla that season, hence the golden rule is 50 and not 49 in the first place
2001 did have some crazy scorelines like that however
2001 was the first season in the NRL era to have limited interchange. The previous 5 years (1996-2000) had unlimited interchange IIRC, where coaches had the luxury of rotating players from the bench whenever they wanted to.
Going from unlimited interchange the previous season to only 12 allowed during the match was obviously going to take some time for teams to used to, leading to players such as Mark Tookey eventually getting phased out of the NRL. Hence, there were many high-scoring matches in 2001, as defense pretty much went out the window.
Not to mention, many of the Sunday games that year were played in above-average temperatures which, combined with the limited interchange, contributed to many high-scoring matches.