Well, as you probably remember we and our Vanuatu partners were the first ones to bring Bir Kar (and indeed most other single cultivars beyond Melo and Borogu) to the international market.
It wasnt easy. Unless you can process all kava from green and are able to identify cultivars on the basis of their morphological features (which requires looking at stems and leaves) +lab test batches for extra confirmation, it's hard or impossible to guarantee cultivar purity. Especially when farmers dont pay that much attention to what cultivars were planted in their gardens (or rather what cultivars to harvest when they were taking it them to processors). This last challenge has been mitigated slightly in the recent years as now farmers supplying our Vanuatu partners know what cultivars to plant and harvest. There was a significant "first mover disadvantage" in this space, but even today it is more difficult and time consuming to do single cultivars than random blends. But clearly there is a market for single cultivars and many customers have their preference and want to try different cultivars. This has led to more exporters and vendors making an effort. Sadly, in some cases not that much effort - we have all seen some kava advertised as x cultivar that almost certainly wasnt that cultivar (one could tell by even just looking at COAs published by the very vendor claiming to be selling said cultivars).
But yes, drinking single cultivars is, in my view, the way to go and reflects historical, traditional approach of paying attention to cultivars. It also makes more sense with better processing techniques that preserve more freshness,unique aroma and features of kava.
As for new cultivars, there are still quite a few decent ones left to be explored, so watch this space
