A big part of why many JWs haven’t [ abandon(ed) that allegiance] yet is because (credit where credit’s due) up till now, the WTS has done a really effective job conditioning them to think that there’s nowhere else to look.
There's another factor which has served the Org strangely well to date, but which they are now tinkering with to their peril and that is: predictability. For many decades until recently, the JW way of life and "party line" on most matters was pretty predictable and well-known by all (on the inside at least) - so for existing JWs, they knew what the "boundaries" were, and as long as they were "happy" with that, they would not walk away or rock the boat.
The irony is that now, in making so many changes in the past decade or so - though many of them were needed and much belated - the Org risks alienating the longer-standing members who now don't really know what their "religion" stands for.
That especially affects the ones who were kids or teens just before the changes. They grew up being told they had to believe in and behave the way JW life was back then, and just when they have learned it and may have decided to stick with it, suddenly it all starts changing.
We talk a lot about the effects on the 40 or 50+ year veteran JWs, but what about these young adults? Just when you think you "know" what you believe, it all starts changing around you. And then you see new GB members appointed who are maybe the same age as your own parents, or even slightly younger. And maybe even new elders appointed in your congregation or circuit who are your own age, or just a couple of years older! A big contrast to the previous "older" men who may have seemed to have "wisdom of age" on their side when you were growing up and probably at least sounded as though they knew what they were talking about.
How likely are you to feel confident that your "leaders" now know what they're doing, or that you wholeheartedly trust and believe what they say? And that you can invest the years of your 20s, 30s, 40s ahead in your active adulthood into supporting them? Or would you be more likely to say "---- this, I'm out of here!", or at the very least, to ease back on the accelerator (if you were formerly a keen young pioneer or whatever) and put the "Truth" on the backburner while you get on with the rest of life?