Too expensive? Look at the most expensive Scan-speak and diamond Accuton.
When considering the resources and knowledge of the Directiva team, its seems a waste not to use state of the art drivers to achieve the best result possible, within a reasonable cost.
$100 vs $425 will lead to an $650 increase just for the woofers, but when weighting everything, and considering the goal to obtain a state of the art speaker, $650 seems a fair price to pay. The Directiva V1 had a boom of $1415
for a pair of speakers, which is almost a bargain considering how good they are.
We already know how small the impact of electronics is, and how important speakers are in the final result, so aiming for the best speaker we can reasonably achieve seems to me the ultimate goal.
Even if when using the "best" drivers available, within a reasonable cost, as the Purify is for $425, which is more than 4 times the price of the $100 units, without being 4x times better, it seems to me a good compromise to achieve a state of the art speaker.
Lets not forget that in this hobby, there are people who spend much more than that in power cables or cable lifters