I think you look at the ways that different sports have developed, and you can understand.
Australian sports have been more regional based when they were created, so there's been a gradual merging of teams into different leagues, which were generally even and had a wide range of winners to start off with, so as more teams were admitted there was an emphasis on providing those teams with the same opportunities. The tyranny of distance means that only the uber-professional teams can afford to be flying around the country every second or third week. There's no way that a team that came up from a feeder league, for example, could be self-sufficient enough without the league pouring ridiculous funds into it. Would help no-one. Remember, the VFL (which developed into the AFL) was also a breakaway league.
English game has to have it. Distances aren't as big an issue (trip from Manchester to London took half an hour by horse and cart in 1893, IIRC) and there are such big financial incentives which are not administered by the league/admin bodies (as such, believe it comes from Sky and sponsorship) for promotion. It's what the game is based on, and the simple fact is that if you used equalisation strategies, players can leave for other markets. In the AFL, NFL, MLB, NBA, that option isn't really there, it's the pinnacle of their sport, and the skills aren't easily transferable to another game (see League, Union).
But I'd compare it to the Super League, there's such a big division between the haves and have nots, from what I've seen, that it's a game that would be better off concentrating on the top 10 teams (they act and market like franchises anyway) and closing the gap, reduce the heap of thrashings within the top division and provide some temporary support to the weaker teams. I guess it would kill off the Cup though. Especially if the NRL's cap becomes bigger, it'll make the focus on developing English players more, so will be interesting to see how it develops.