I definitely agree, the article uses some messy statistics. An additional concern is that if your argument is that 10 investments reduce variance, you want to

I definitely agree, the article uses some messy statistics. An additional concern is that if your argument is that 10 investments reduce variance, you want to keep in mind correlation effects. The probability of one investment failing is likely to be dependent on other investments from the same domain, due to the nature of booms and busts.