?? Inflation in the U.S. and Canada has been low for the last several years; it has even been negative during part of this time. And we're talking about product categories that didn't even exist ten years ago. So I don't think that inflation is a major factor in this case.
Rather, I think it's the simple fact that professional audio products (especially those of the highest quality and reliability) are priced higher when and if there's enough demand to support such prices, in relation to the available supply. Where there's more competition among suppliers of comparable quality, prices come down; where there's less, prices come down less or they don't come down at all.
With stable product categories that are available from a number of sources (e.g. microphones), prices tend to decrease substantially over time if you use "constant dollars" as the basis.