Take this from the perspective of someone who was very actively involved in organized dentistry, on a local, state and even national (as one of my state delegates to the ADA for 3 years) level. I stepped back a bit over the last few years due to the time constraints family wise of having 2 very active then middle schoolers, now high schoolers at home, but plan on getting very active again in a few years when both kids are off in college.
There's a bunch of value in organized dentistry that one often doesn't fully appreciate, and it doesn't always come in the form of CE credits or a very solidly written journal that you receive monthly.
The ability, when it comes to the legislative side of dentistry, in particular on a state and national level, for the various members of the ADA who volunteer their time to be a very active in the political lobbying for our profession to say that roughly 60% of all dentists are members (the American Medical Association by comparison is at roughly 1/3rd membership, does help and carry some weight as we are advocating legislatively for what's best for our profession. You often don't see or hear of many of the legislative "victories" that organized dentistry has won (and sometime those victories may have more to do not with getting a bill passed, but with preventing a bill, that would have negative consequences for our profession from even making it out of committee so it could be voted on.
Again, this may not be as apparent as some CE offerings or JADA showing up monthly, but it does have significant value for the profession