As someone who works with traders, I'd say that the randomness/unpredictability of the markets is part of the reason *why* traders are so reliant on their models.
Otherwise, it's all just blind gambling (which it isn't far off, anyway).
The advent of full on algo trading means that random events in the market have the ability to wipe out tons of capital because the models predict (e.g.) a global crash when it's just a blip. (Extreme example)
The other part of the problem is that traders are nowadays just glorified clerks in that all (well, 90%+) of the actual calculation and predictive work is done by complex platforms (or Excel), so they don't really care or have exposure to the real risks behind their trading.
Coupled with the huge bonuses they used to get (I'm in London where bonuses are being denied; is it the same elsewhere?) as long as they showed *quantity* of trades, it was always a recipe for disaster.