An anticipated rush to replace obsolete units operating in the outlawed spectrum never materialized, at least in part, because of confusion caused by the new law.
Rather than replace their mics, lots of wireless users simply sat on the sidelines or ignored the law. Many were too confused to risk spending the money that was required for replacements.
It appears that this log jam has finally broken and that sales have turned around.
Lots of of the major manufacturers are introducing new models and sales seem to be following.
Mic producers like AKG, Shure and Line 6 report interest in their new products, a higher level of understanding from buyers, and interest in new products. New offerings at lower price points seem to be of particular interest.