So basically, he is bringing out that his studies of the data out there concur with this guy Starks, in that JWs are in decline in US, Canada, Austrailia, and New Zealand. He theorizes that it could be due to certain stricter religious movements reaching "market penetration," and that there is only a certain small number of people in the population that will be itnerested in such strict religions in the first place. Also, he thinks that "new forms of Protestantism" offer more attractive options for people than the "straight-laced" religions of LDS and the Witnesses.
He later goes on to explore the notion that strictness is necessary for the growth of a religion. This is something that has been discussed quite a bit on JWD over the years: whether the WTS is becoming less strict and more mainstream, and if they are, whether this is in their best interests. Some people here have explained that such leniency in church policy and doctrine can only reduce loyalty to the organization.