I don't see the extreme cost in this process. You can make an 8x10 Palladium print with a drop of Na2 on a paper like Platine for about $4. If you are willing to buy in large quantities and keep track of market prices, you can make the process even more affordable.
As for the interest in pt/pd printing waning, the opposite is true. I've been teaching pt/pd for 11+ years and every year have had more students than the year before. Two of my workshops were overbooked this year and I have more offers for teaching than I can make time for. IMO the process is easy, fun, economical and most importantly beautiful. What's not to like?