A big reason is the Rekordbox software used to manage song libraries. Another is standardization - DJs move from club to club and encounter the same hardware se

A big reason is the Rekordbox software used to manage song libraries. Another is standardization - DJs move from club to club and encounter the same hardware setup. They are very well built, work in rain, ... Today you also have influencers which are DJ-ing, but they don't have the skills, so either they have a pre-recorded mix or just use the CDJ auto-mixing features. Having a standard device they know how to operate is again critical.