There are a few problems, as some have pointed out already, with getting rid of Origin.
Firstly finance. As a revenue earner, it earns a lot of money for the NRL, which then flows to the players, clubs, and helps provide funds for junior development. That money goes direct to the NRL. If you get rid of it altogether, you are unlikely to make it up in revenue from the broadcast rights deals for the NRL competition, nor international rugby league either.
Secondly, broadcast rights. As they currently stand the NRL are obligated to provide so many games per week under its various broadcast deals to its broadcast rights holders. As such unless those deals are re-worked significantly, at least one of those rights holders would probably object to the NRL competition being "put on hold" for Origin matches. Why? Simple, non-free to air broadcasters have been unable to broadcast them, Channel Nine insist on exclusive rights. That combined with anti-siphoning legislation also inhibits non-free to air broadcasters unless the FTA rights holder is willing to allow simultaneous broadcasts which, to date, Nine haven't been.
One other thing many people overlook with Origin is that playing in origin matches gives players exposure to his intensity, high pressure matches akin to finals football. That is what helps clubs who have those players selected in the longer run when those teams make the finals, its players have some idea of what to expect.
Its a hard one to work out as there are a number of issues. Fact is though that it won't change until someone work out what games need to be lopped off the rugby league calendar if you want Origin to be played on stand alone weekends. If you look at the current rugby league calendar, we have trials played in February through to international matches played in november. You can't just say "oh we'll make it even longer to add in stand alone weekends for Origin" as it would impact on the mandatory time in the CBA on which players are on leave at the end of the season.
In terms of games we need to worry about "quality" of the games played as opposed top "quantity". For example, in the USA, the NFL which has a regular season comprising 285 matches which earns them $110 billion per season. The NBA by comparison has a season comprising 1,320 matches which earns them approximately $2.7 billion from its domestic broadcasters with another $700 million from its international broadcasters. Even Major League Baseball only earns $1.762 billion pear season for its 2483 game season (note, this figure excludes revenue for local TV rights deals negotiated by MLB clubs).