Interestingly I've heard anecdotal evidence from a couple of people lately, where the champions league has become the main drawcard in their household. A friend with 3 young boys said they love their football, and will record and watch the champions league games after school, but that they aren't very interested in the EPL. They want to see the messis and ronaldos, as well as the top english clubs, so the champions league is the place to be. One of the boys has become a Roma fan, and another an Altetico Madrid fan, from watching that regularly. They're all 12 and under.
Another friend said he's observed similar behaviour in his son.
Neither of them are Dads who had a footballing background, so they haven't bought any english team allegiances to the table, and this is what has organically resulted.
Obviously it's just two instances so I won't claim it as a trend, but food for thought.
I was thinking more in terms of who the paying customers are at the moment, the market Spark and Sky are squabbling over, but the next generation is certainly interesting. Anecdotally all of the NZ fans of a similar age to myself that I've met have almost always supported an English club, with the handful of European club supporters I've met being from those countries. But with the amount of kids you see wearing Ronaldo/Messi/Neymar jerseys it's conceivable that English clubs won't be the sole focus of the next generation of fans here.
The Premier League still seems to be such a 'default' league in NZ, in the sense that it's the only league you'll ever see given regular coverage by our news outlets. Can't recall ever seeing La Liga, Serie A etc popping up in a sports segment on One News, yet they'll always run through all of the PL results and show a handful of the goals from a given weekend (as an aside will be interesting to see what they do next year given they seem to crib all of their highlights from Sky).
Ryan Thomas is essentially anonymous playing at European Cup-winning PSV, yet if he snared a move to a Brighton or a Bournemouth he'd suddenly be deemed relevant by TVNZ and would get the Wood/Reid treatment in terms of coverage. But I guess the Eredivisie will always be a bit too niche for our mainstream rugby-lead sports sections.
Availability of broadcast-quality footage is your answer. During the PLP days even the EPL footage often looked a bit dodgy.