Yes the diminishing USD is responsible for price increases, but that wasn’t my point. When the 645D was introduced, a new wide angle was an immediate need. Pentax chose to introduce a extraordinarily wide and expensive lens for the 645 format. A 30mm f/4.5 would have been easier, less expensive and a better seller – the 25mm could have come later. Based on your comments, the 90mm will also be a spectacular, but an expensive lens as well.
Just my two US cents (currently worth somewhat less than before),