Really? I don't think that the sword market is declining. On the contrary, it is growing and growing, and adapting to the times and opening up more and more to the foreign market with English language websites. The Samurai Museum is the example of this.
I think we've become quite spoiled by now. 20 years ago, buying in Japan was an adventure, communication was very rudimentary, paying was really exciting, and there was no tracking. Only customs was easier, at least in my cases.
Back then, if you were looking for a sword of a certain school, you would get one, rarely two offers with a price that said buy it or leave it.
Today, with a little research, you have a wide choice. Pure luxury. Also the service has become much better, swords polished, swords to Shinsa, experts can ask, literature, sword forums, etc..
Yes, this brings opportunities, but also problems. Chances to find with a little patience exactly what meets the own demand and budget. But also the problem to bring something on the market, which does not get the desired attention and the once invested amount is halfway recovered, because interested parties have a wider choice.
Where real quality always finds a corresponding customer.