I believe growth will slow due to greater exposure of the religion online. But I don't see that killing the org. altogether.
Watchtower is very good at brainwashing JWs to practice self-censorship by demonizing apostates; by telling them to avoid apostate information; and by telling them negative information on JWs is all lies.
Sure, many young JWs and pre-JWs will get access to TTATT - those brave enough and rebellious enough to defy Watchtower propaganda. Such ones are typically in the minority. Plus, even when JWs are exposed to TTATT a large percentage of those exposed put up psychological walls of denials and rationalizations so that the TTATT has no real effect beyond inducing a temporary bout of cognitive dissonance.
So yes online exposure will have an effect on growth but the effect will not be overpowering. Also, once Watchtower notices that online exposure is having a significant effect they will step up on the propaganda warning JWs not to visit questionable sites and not to read negative info. on JWs. They may even return to demonizing the internet as a whole, telling JWs they're only safe visiting the organization's website(s).
Think of the fact that there's mountains of scientific information online proving evolution and exposing creationism. Does that fact destroy fundamentalist creationists? No. Neither will online exposure of JWs destroy the organization altogether. The worst that will happen is that they will get very few if any members from the non-JW public and their growth will slow to near natural population growth through the baptism of born-in, indoctrinated-from-birth children of JWs.
Online exposure will not be the factor to put an end to the religion. It would be one of multiple factors.