I had a hubber score of 100 by the time I had been here 4 months and only had about 10 hubs. Part of getting a score of 100 is just answering questions, hubhopping and commenting. I do all those things on a regular basis. That is probably how this person got them also. Average in the hub scores and if you are particular about punctuation and grammar, you can have high scores.
I do not think niche hubbers are more successful than any other. Someone who writes for Google will appear more successful than someone that writes fiction. Are they more successful? No, they just are more searchable.
I think a lot of people write for many different reasons and it depends on how you feel about the results of your writing on who is more successful. Many fiction writers hone their skill on HubPages and go on to publish books. They feel that they are ultimately successful and are very happy with the results of their hubbing.