A _lot_ of data is necessary to call a result if the effect is relatively small. If not enough samples are taken, there will still be a "formal" result, but the level of certainty of it will be low. Of course, depending on how accessible that page is, it might take a very long time to achieve significance.
How much certainty do we need in the result? P-values are generally considered not a great measure, but they are standard, and they are what they are using (if I understand correctly). This can give you an idea of the numbers we'd like to see for that value: https://xkcd.com/1478/
In other words, only the first A/B test has conclusive results: accordion is worse than wizard by 30% with 0.01 p-value. Of course, you can see that there's a significant result _because the effect is large_. Note that this gives us an idea of the _resolution_ of their test system (i.e., how many As and Bs they have and how much effect they can see with their test). So we know they see an effect of about 30% change.
Now: all the other results are wrongly reported. The next four are mistakenly reported as "no statistically significant difference in performance." This is a false statement. Having high p-values means that any effect is below the resolution achievable with those numbers. In other words, the correct statement would be either "the experiment was inconclusive" or "the effect, if any, is less than 30% change". This is quite different from claiming "no change."
The last result has 28%, and it has a p-value of 0.05. I would _not_ accept it at face value. Such a p-value means the result has 1-in-20 chances of being due to a random fluctuation of data. There are six such experiments just in the post, so it's not unthinkable that the effect could be a fluke. More info on this here: https://www.xkcd.com/882/
All in all, the only result found is that _in their case_ the wizard was much more effective than the accordion. The rest is not supported by the facts presented and furthermore any generalization of the result outside their particular case is unwarranted.