The 'mod DJ' scene peaked a few years ago and is showing signs of fatigue, but it's still there. For years there was an event called Mod Chicago, I got the lowdown from people who attended that were not really part of the DJ scene but many of the top DJs were from overseas and they played the records that are (derided as) 'mod floorfillers' and a sizeable crowd of people were seriously into it. There's a few factors at play here. One is the 'hot box' factor - people keeping a relatively small collection ot records and frequently turning over records that they have had for a while because of overexposure or desire to change. Another is the 'hot genre' (my own term) where people who were into, say, 1960s Northern Soul oldies decide they want something different, 'sell up' (as they say in the UK) their collection and immediately go on a spending spree for 'mod' or 'rockers' or 'R&B' - and since they are by nature compulsive people they don't bother to wait out deals, they jump. Also, the well established rockabilly/rocker crowd has been slowly creeping into the 1960s and garage type sounds (classic example - "Let's Dance" by the Excels or anything by Floyd Dakil).
I would never say people are making a living as a 1960s DJ and getting enough income from that to buy $600 records frequently. I would say that there are plenty of people with enough money to buy expensive records all over the world. I've often joked to younger people that they should go to China and start a original record collector/DJ scene in order to keep the value of their records high in the future...