The biggest disadvantage of desktop publishing is it killed the market for design services.
I've been doing this even before there was desktop publishing. We used to need two machines to set type--one for body copy, another for heads. Back in those days, typesetters made decent money, because they had a rare skill. Today, you can do the same thing better in Microsoft Word--and everyone has that.
Instead of designers being worth $35 to $200 per hour because they had mad skillz, now they're worth as much as the guy who drives a forklift at Home Depot.