As others have said, the JW religion will probably be around for a while.
They will try to reinvent themselves possibly. They will still keep the public preaching work to some degree to keep their charitable status, as has been mentioned.
What I really think will greatly weaken them, in the not too distant future, is the demise of those very elderly ‘faithful’ Witnesses.. When these people go, so will their donations.
As a result of this, the religion will also lose more numbers.. In my opinion, other JW family members presently hanging on and ‘faking it’ for their elderly parents’ sake, will leave.. Once the elderly Witnesses die, everyone will see some family members just stop coming.
Ultimately, at some point in the future…the religion will resemble other defunct sects in the USA. Time will tell.