Glad I was right here.
As someone who has only learned about the formal or orthodox parts of tennis recently the lack of agreement over what constitutes a certain rating astounds me. Those terms are thrown around all the time in discussion. Why is this? The one source I have gathered is that different regions have different skills rated at the same number. I remember seeing this in one of the drama threads involving MEP I read when I was lurking last year. I think the core of that argument was that 4.5 Atlanta = 4.0 New York and that New York was more correct according to what the USTA tries to say the numbers are supposed to be.
Don't fret, there's disagreement on these forums from some people, in the real world there is more agreement.
I've proposed the geographical difference theory before and some people would respond that there aren't any differences because they captained a team from the flyover states to a national title, so how could a region like Texas or California or Atlanta have better rated players if their team didn't win nationals every year? I personally don't think one region has to win nationals every year to have the larger group of better players. If you venture to other threads Utah is headed toward being a 3 time national champion at 4.0 via their super captain, does it make me think UTAH has the best 4.0 players in the country, the ones that don't make it to nationals? No, to me it's further proof that success at nationals has little impact in assessing the skills of those left behind.
As far as skills or looking good and results,
Take the highest level of any ratings tennis in NTRP, it's tournaments, large ones and sectionals/nationals. The players winning large tournaments at 4.0 and 4.5 and slugging it out at sectionals and nationals all have good looking strokes, a majority are ex college players who've played since they were 10 or younger. The self-taught adult rarely wins at that level, if we are talking 18 + and even though I am getting older, in my world, 18+ is tennis, where the real competition is.
Now, back to geography.
It's to everyone to decide. First, the most frequent argument I've read whenever this comes up is, if one region is better, why don't they win nationals every year. I don't think that is a good way to look at it.
What I have personally seen at 4.0 and 4.5 between large tennis areas and smaller:
Memphis and Little Rock and Nashville and Mississippi: 4.0 leagues will have 1-6 teams, 4.5 leagues will have 0-3 teams. Memphis and Mississippi will have 0-3 singles tournaments per year and very light participation. Little Rock impressively might have 6 singles tournaments, but the same 6-10 players, the same, will be at every tournament, playing each other, creating their ratings. This I've seen for 3 years, no new players, just the same guys over and over. Most areas have zero 5.0 play occurring.
A large area like Dallas: 4.0 leagues will have 3 "conferences" with 10-15 teams each with max rosters. 4.5 leagues will have 10 teams. There will be 1-3 singles tournaments every single weekend in the summer. Dallas city championships will have 3-5 teams that could win against any team I've seen in non Atlanta Southern. There are entire 4.5 teams of ex-college teammates who've never been a 4.0 in their USTA life. In the smaller areas there are many 4.5 teams that put in the time and effort to claw their way to 4.5 beating all the 4.0s around them (all 20 or so in some areas).
I've also called around looking for clinics and I have no idea why but the pros would ask where did you move from, "Dallas" then they would make some remark like oh well, then you'd probably like this group better, it has the level you are probably used to playing. Strange really.
Women are a little different, but small ancedote, there are 4.5 W in non-atlanta southern who fought their way through all the 4.0s in a season or two and made it to 4.5, athletic and self-taught. Then somewhere like Dallas will have multiple teams full of division 1 and 2 women who started their post-college careers in Dallas from all over the US, they've never been a 3.5 or 4.0, and yes, they are very different in skill level to the 4.5s in southern. They also beat down any women in Dallas that work their way up to 4.5 and send them back to 4.0 quickly.
The multiple tournaments in larger areas can have 20-30 players per level, the smaller areas are lucky to make a tournament and if it makes have 4-8 players.
My conclusion is that larger areas just have more players, playing opportunities, ex-college tennis players, and more "friction" churning out a mass of more tennis skill. But, you may draw a different conclusion.