I’m not sure that many sports fans who are paying for Stan Sport would have difficulty switching to Kayo or Optus, and certainly not Netflix. I take your point on the news conglomerate and I also like the weekly free to air that nine offers.
Every time you ask people to make the jump there are those that are going to drop off. There's every opportunity to pick them back up down the track (along with new eyeballs from the platform you've moved to) but there will be a hit. More important though is the eco-system that has been built around the game - there's a lot Stan are doing to promote the game via things like socials and weekly shows. That's not to say a new partner wouldn't do those things, but it takes time to get up to the level Stan are at and there is a cost associated with that in terms of fan attention.
Added in is the quality of the broadcast product itself - Stan are doing an excellent job here, and their coverage is often held up as gold standard outside Australia. It's taken them time to get there though and any new broadcaster would take time to get there themselves. During that period you're attempting to attract and retain fans with what is effectively an inferior product (on field aside) and that brings with it a cost.
Hell, there's even simple admin costs at RA and the super sides associated with changing a bunch of day to day minutiae in who you're dealing with at a broadcast level and how those interactions are managed that will add up, particularly in the first year or so.
None of this is to say we shouldn't be considering all our options and open to switching, just that any other party is likely going to need to beat Stan by a decent margin ($1 million maybe? It's hard to tell from the outside) for us to start considering it. Probably the ideal in that circumstance would be a hefty as a signing bonus to ease that transition.
