which wouldn't have been possible before DSLRSs
I'd say Standard Digital video in the era of the VX1000 preceded the practical use of DSLRS for video...the quality of the preamps just declined and high level production required double system.
DSLR brought with it even more limitations like with audio metering, so it forces people to look outside the camera for solutions.
Meanwhile, if you're weren't a one man army, there were better tools on the market, but it becomes a matter of budget. A working cinematographer/filmmaker needs the most versatile tools possible.