Why the hell do 31% of the members have no established or provisional rating?
A few statistics from the USCF database

That number is also more than I would have guessed. Apparently, a lot of members simply don't wish to enter tournaments at all, for one reason or another. I do know several people who love and follow chess, but they don't wish to compete.
Note that stat includes ALL the records. Let's check more recent data...
There are 360,574 records with memberships that are current or have expired within the last ten years... since 6/30/2004.
Of those 360,000+ records, 114,169 of them (31.66%) played 25 or more games... enough to acquire an established, regular rating.
166,715 of them (46.24%) played in at least one tourney and acquired a provisional rating.
So with this data, only 22.1% of the members over the past ten years did not acquire a regular, established rating or a provisional rating.

Still seems like a lot. How are these people signing up without playing a game? I would've figured the vast majority of new signups were people physically at a tournament registering with USCF for the 1st time.
Can you see the ages of the players when they joined? My next guess is scholastic players whose school registers them as part of their chess club, but they never go on to play any rated games.

No, in the Golden Database, the age of the players is not listed in the file.
From what I've read, there is a new, experimental database, in an XML format, that supposedly contains a bit more information. Maybe I will download this database, and see if I can figure out how to extract data from this XML format. (Something I've never done before.)
There are some people who might sign up to become a USCF member just so they can read the monthly magazine. Or maybe they sign up with the intention of evetually playing rated games, but then later "chicken out" for whatever reason But I agree with you. I would suspect this percentage to be very small... just a few percentage points, not 21 to 30%.

You also would have to consider that some people sign up only to play correspondence chess and have neither the time nor interest in playing in OTB tournaments. In those cases, you'd still have an active individual with no established regular rating.

Good point.
Also, just to be clear, there are a very, very small percentage of players (less than 1%) that don't have a regular rating and they don't have a provisional rating, but they DO have a blitz rating listed.

Great insights. I suspect there are many scholastic players in the bunch. It would be interesting to know the rating distribution of active players with an established rating.
Interesting. I suspect the reason there are so many total records but less active players is simply the competitive nature of the game. People join and want to see how far they can advance. Once they plateau, or stop improving their ratings rapidly, they will lose interest and not be so active. So I'm curious what is the turnover rate, how many players drop out each year -- fail to play in any new tournaments.

Kids who obtained memberships and quit after just one tournament might account for many of the non-playing members. Also, could it be that some people join just to get the magazine?

Kids who obtained memberships and quit after just one tournament might account for many of the non-playing members. Also, could it be that some people join just to get the magazine?
I wonder how many are listed as non-members. I think this happens when e.g. a parent uses their credit card to buy a membership for a child. At least I've seen some parents listed as non-members (you can find their names in the USCF search).

MrEdCollins
There seem to be some inconsistencies in USCF data. I looked up the stats for a 1611 rated player. He ranks 9457 out of 63907 active players (played in at least one tournament in the last 12 months). The Post 1 graph shows about 15000 out of 40000 rated above 1600. A much larger percentage.
I may be comparing apples and oranges because there are so many variables (active, inactive, total, juniors, scholastic, established, provisional, etc.)
Note: This piqued my interest because the other graphs that I have seen have the peak at 1100 or 1200.

Kids who obtained memberships and quit after just one tournament might account for many of the non-playing members. Also, could it be that some people join just to get the magazine?
That's basically how it goes. A lot of people play 2 or 3 tournaments as a kid and that's where it tends to end. The people that actually play the 20-ish games to get past the provisional rating are usually more into chess than most.

MrEdCollins
I did some research, and I was comparing apples to oranges. When I look up a player's ranking, active is defined as having played in at least one tournament in the last 12 months.
The Golden database appears to define active as anyone whose USCF membership expires after the end of the year in which the data are published. That would include many players who no longer play in tournaments. Higher rated players are probably more likely to extend their memberships beyond their "playing days," so that would account for the distribution curve being skewed to the right.

Kids who obtained memberships and quit after just one tournament might account for many of the non-playing members. Also, could it be that some people join just to get the magazine?
Pretty sure we covered this 3 years ago.
At the USCF website, in the Member's Section, the "Golden Database" is available for download. This database contains the member name, USCF ID, member expiration date, member state, and rating of all current (and non current) members.
Not that anyone cares, but here are a few statistics from that database:
Using Excel, a lot more data and stats can be extracted and determined than this. This is just the tip of the iceberg.

Here's the rating distribution graph, for active members with established (regular) ratings: