I tend to think that a constant percentage of world population is mentally damaged and/or unformed enough to buy into it. That constant will never alter. The WTS just has to keep drilling. It has some likeness to the case of prospecting for oil. There are untapped world endowment (50 years of petroleum left on this planet), there are reserves which are pockets that have been speculated and marked, there are the methods of drilling and the methods of refining. All the reserves of surface oil are gradually drying up, but there are vast amounts of oil in dangerous areas (undersea) that will require a significant increase of technology to extract economically. Unless that technology emerges, that oil may remain there for some time, pushing everyone towards electrocars, et al, the sooner.
The WTS has to find new technologies for extracting equal resource from increasingly unwealthy and uneducated populations. Or, they must cut back their requirements and overhead. They do appear now to be playing the part of the desert succulent, which gorges on water in favorable season, and withdraws in unfavorable. It's hard to see where the next surge of economic moisture will come from, but there's always the energetic tug of politics which by shear odds always have a chance of happening in such a way that they can retroactively pronounce that it was forseen just so, and send even the wealthy western foxhole seat-warmers for their wallets. (I think, I may be wrong.)