What happened to Sauvignon Blanc Semillon blends?

It's a good question; blends are also underrated in my view. Perhaps there's a (local) perception that the "first wine", that sees the most care, is the single varietal wine, and the blend is the rest. Perhaps having one grape variety is easier to understand/sell. Cabernet merlot blends from Coonawarra and Margaret River are perhaps another example (I am thinking Balnaves, Vasse Felix), although there for some reason the blends can sometimes seem to attract lesser care (and price) than the single varietal cabernet sauvignons.

"Is it a case of our mono-varietal drinking culture simply unable to love a blended wine?"

I'm not so sure about this. If you go into your standard liquor barn, there are plenty of red blends doing fine.

Market dominance is often as much about shelf presence and pricing as it is about an understanding of specific blends. I am not convinced that most consumers could pick NZ sauv bl vs an AUS sauv sem. However, in most local liquor barns you'll get about 25%-40% of white wine shelf space devoted to NZ sauv bl. Esp. in that all-important $10-$20 category. And most whites on special seem to be NZ sauvs.

To some extent, this will be down to consumer demand ("give the punters what they want") but it will also be down to the economics of supply.

I went and had a look at NZ's wine production figures. A whopping 68% of their wine production and 83% of their exports are for sauv blanc. And we are their biggest export destination (more than the US or the UK). In contrast our sauv blanc production is less than a third of our chardonnay production.

Their wine production might be around a quarter of ours at the moment but theirs has doubled since 2004 while ours has decreased in the same time period. During this time the NZ$ has been pretty weak against the AU$ (although they back to near parity now). This obviously gives NZ imports into our market a price advantage.

In some respects, NZ have hit a lucky streak with sauv blanc in Australia. We were ready for lighter white style and they had the wine to fill it – along with extra capacity at lower cost (in a similar manner to Australia displacing old world producers a few decades ago).

Now I'm not a big NZ sauv blanc fan. I very much prefer wines such as the Sorrenberg Sauv Sem and the Fraser Gallop Parterre. But those are niche wines and I am out of step with the wine-drinking public. However tastes change and NZ's reliance on a single variety may leave it vulnerable when such a change occurs.

Kind of following on from the above post, I'd suggest that Vasse CDW and Evans & Tate CDW sell sh*tloads but mostly through the chains. Price is probably similar to what they cost 10-12 years ago too!

Devil's Lair Fifth Leg White was another big star back then, when it still had DL on the label.

"Yet still straight Sauvignon Blanc, with all of its monochromes, wins out in the end?"

Going back consumer taste issues rather than production-side issues, consumers of NZ sauv blanc often say that it's "easy" and "clean" (similar adjectives used to describe the pinot grigio that has become popular in the UK over the last decade or so). Is "interesting" what the majority of consumers want from wine? I'm not sure it is.

As there hasn't been a very recent bushfire or shark attack, this is THE hot convo topic in Margs of late (except for the Wallcliffe thing, but I won't get started on that).
The NZ SB thing has been around for yonks – it certainly has done the most damage to MR/WA SB/S, but the worst of that was done in the mid-naughties after which things seemed to stabilise a bit. Kiwi SB has come down in price over the years, so kills us even more at the cheaper end of town, but that is gettting into a different ballpark which WA can't even get close to afford playing in. The last couple of years seems to have seen salt rubbed into those wounds though. My guess is that the increased availabilty of other crunchy, dry whites with reasonable price/quality done it – ie the boom in imports and rise of domestic versions of "alternative" varietals.
There's also always the simple and unpredictable whims of fashion. More than ever before, reliable quality and drinkability are taking a backseat to story…to get a listing on many East Coast winelists, a wine needs to have some sort of hip angle. Despite (or perhaps because of) having 8 monotonously good vintages in a row, WA is way behind on developing hip stories about how they grow and make their wines compared to many in the SE of Aus.
Simon.B.