With the fall of Hobbico, I don't see many distribution channels for Tamiya at the moment. Horizon carries some Tamiya, but very very limited.
I bet many of the smaller websites now having to get their Tamiya products direct whereas they were using Hobbico/Great Planes as a distributor in the past and able to take advantage of their MAP pricing. Since Tamiya has always directly sold their products at MSRP, I have a feeling this is a likely candidate for the price hikes