Yes, BW, BB, Chip, Kosher, Tiger, etc..have all had bad runs..some as long as a year or more. Then again with some of them, some of the losing sides are at times designed disinformation, thus can be misleading.
Many old school sharps like the Lil Lunatic, Tomatoes,etc..before passing away, could have years that were absolutely horrible, lost tons, but also had runs and years where they made absolute fortunes. it happens to all..even the most talented and informed.
That said, they still did things better than others that may have had equally bad years. They generally were originators/not followers, knew where the line would go with better accuracy, got better numbers early to lay short/take high at close, had better contacts, better info, better outs, etc..
Even the best of the best have needed backing or bankrolls reinforced at times, the difference with the Elite Pros is, their track records, contacts, outs, etc..they have/had places and people to go to for backing or bankrolling when times were tough.
As a teen, I used to ask an uncle of mine, how he had the balls to keep firing when absolutely burying himself following losers and sendouts, he replied, "You can't hit homers, unless you stay in the box and keep swinging!"
Go read interviews with BW, BB, Bob Martin, Lem, HH,etc..they all had times when their backs were to the wall.