It just seems to me that gentle decline will be hard for JWs to pull off.
Why? I'm not so sure they are so dependent on prosperous growth. Growth has been declining for years, and even JWs realize that in developed countries (outside USA perhaps), "native" JW has already been declining for many years. Most of the new people are refugees and children only.
As happened with the Worldwide Church of God. Their crisis was also prompted by money problems.
The article you link to says that after the death of Armstrong, the church changed their doctrines and that was the cause of the splintering. So not per se any money problems (as far as I read the article).
It's well possible to put a spin on the slow decline too. "In the times of the end, Satan will try to lure people away from the truth." etc... "Be steadfast!" Gult tripping and fear mongering continues to work.
Besides, a lot of JWs will need serious help and feel lost if the organization would really implode. Who hasn't heard of the "where should I go?" argument (in case JW isn't the truth).