Well I was in a discussion with industry specialists at DJ Meeting Germany and they said that they invest a lot more into the controller market currently as the upgrade habit of controller DJs is much more regular than other DJs.
The usual turntable buyer buys his Technics Mk III or better and will use it for 15+ years (if they DJ that long), where some controller DJs update yearly with the average between 2 and 3 years.
Also the upgrade path when starting out is much faster, some DJs go through 2-3 controllers within their first year of DJing or learning to DJ, simply as a beginner controller is a small investment and if they want to go on they upgrade at least once very fast.
There is still some trend for some controller DJs to migrate (I will not say upgrade since I do not belief it is one) to CDJs after their first year, but many of them stop DJing or put out so much money that they cannot buy again soon, so upgrade will be a far way off.
The installed base of controllers is huge. Many have very basic controllers that you can buy in radioshack, media outlets etc. like Hercules or the entry Numarks and nowadays even the small Pioneers (like the WeeGo) fly off the shelf for home enthusiasts. So the semi-pro and consumer market on controllers is huge, where as in CDJ or turntables the consumer market is near to non existent (except turntables for audiophiles but they are totally different from usual turntables, but I mention it since Vestax has one).
I know this is all a bit vague but that is a summary of what I heard there and can give out.
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