Not that it disappeared completely, but there's less of a need :)
I have no inside knowledge but I expect the sales drop slowly as new users start with ghidra instead of ida.
Most of leaked copies in recent years were specifically bought to be pirated (except Keen Lab one, rip), and as Windows binaries are the actually portable executables now because of ABI stability and Wine, they almost always buy the Windows version.
I've never seen a single leaked Linux IDA Pro and it's immensely useful to have IDA on a real OS without headaches caused by Wine.
Personally, I've switched to Ghidra for most of the things, IDA only when Ghidra doesn't handle something. But then again, personally I never was an IDA customer, beacuse it's too expensive for hobbyist use (and IDA Free is too limited).