Simply don't see it around at elite-level competitions anymore. Ask around yourself, and you'll find that the majority of pros and top collegians have just given up on it. It makes athletes feel bloated and unwell during races. Even worse in the summer as the thirst it brings on is unbearable.
Most elite level athletes have found that there are no true performance gains with bicarb. Maybe that's because they have already reached those physiological limits through training or natural talents.