From what I can see no such thing is happening.I became a JW in 1960 and remained for about 30 years and the numbers of active JW`s today in the world are far greater than they were back then.
And here in Australia the numbers are much higher than they were back then .
So I don`t see that their in decline or have any worries about losing support .
Don`t the numbers speak for themselves ?
Is it just wishful thinking on your part ?