It works for weddings. It CAN work for Mitzvahs depending on the type of parents who are looking to hire a DJ. As noted on DJ Taso's videos, this works with the high end "Super" Sweet 16 clientele as well.
However, for corporate, and 30th, 40th, 50th, 60th, 70th birthdays...MOST sweet 16s. High School Re Unions. Halloween Parties. Holiday parties. School Dances. Store sales events. ...Those emotions, and trying to get a good vision for what they want their party to be like isn't really there. In those instances, it really just comes down to being the most visible, and coming in with the right price for them to book and go with you.
I don't see any DJs claiming to book $1,000 30th birthday gigs out there.
I look at those gigs as "filler" work these days. If the client came my way via referral, I know I have a greater chance of booking them above $500, but know they won't go for $1,000+. If they came my way via the internet, I know my booking success rate is low, and if I really want the gig I quote low on them. They just aren't going to normally pay a DJ higher pay.
If you ain't doing weddings, and/or mitzvahs, you really aren't making the big bucks as a Mobile DJ these days.