This will unfortunately (for djs), be the norm soon. Why should the venues sit back and let outside vendors get all that dough when the can wrangle it for themselves? They will eventually have pro sound, lighting, gobos, video and uplighting. Most people love convenience and this will certainly be an attractive sell to potential couples.
If your target client is the type that want these full blown features, be mindful of the longevity of your investments.
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Not only that Hank, but they may actually hire an "In House DJ", either as a part timer or full timer with hourly wages. They will make more money from the total charge too.