Superleague's problem is its lack of sponsorship and the stupid decision to tie in to a long-TV deal when things have heated up in the TV rights market.
There are far less big brand names sponsoring the clubs than a decade ago, my own club is now sponsored by a local Scaffolding firm, whereas for a good decade or so we had the internationally known P&O. Same can be seen at other clubs, and it has taken a few years for the league itself to recover from the free Stobart sponsorship debacle.
On the TV rights front just as other sports are making SKY & BT have a bidding war, Union have manged to get a Channel5 to outbid ITV for their highlights show, and Facebook & Amazon moving in on the streaming market...the RFL just signed us up to SKY for years, and we can't even get the BBC to show the Super League show nationally at a time anyone wants to watch.
SKY are seeing their slowest growth in years and scared by the growth of streaming (hence the changes to the Sports packages) and even a slight hint of a solid ratings banker like RL going elsewhere would drum up a few more £.
As for Wigan specifically, obviously I am on the other side of the Pennines, but its noticeable their crowds are well down. To be fair to their Chairman he at least tries new ideas to grow his club and the game, such as going to Australia in partnership with Hull, playing a game in London a couple of years ago and promoting a 'big' fixture each year.
One issue I am hearing from fans of all clubs is the poor refereeing standards and the amount of time spent with ball out of play for video ref decisions, injuries (many of which are being faked by the players to get a breather) and 'talking to the captains' night games now gone on way past 10pm for all this nonsense. RL's selling point before was that the ball was in play far more than other sports.
And you could write a dissertation on the RFL's marketing, so i'll keep things brief! a few social media ads last minute to an audience that already follows RL and its social media pages isn't up to the job. Boxing and RU manage to turn any old event in to a 'must see'