What constitutes an expert in your opinion? There are some 2.4 million people playing table tennis in the UK[1], so the top 250 is pretty elite. Just looking at membership in Table Tennis England, there are nearly 25 thousand players[2], making 250 the top 1% of people who care enough about the sport to spend money becoming a member. I'd call that expert. It's certainly not just "ok at table tennis".
I play table tennis so I guess it constitutes me as a table tennis player. In order to become a member of England Table Tennis Association you just have to pay a fee. They don't check whether you even can hold a racquet or not. So out of people who pay the fee it makes you "elite". But out of 1000 people who are ranked it makes you average even in England.
Don't get me wrong. I am all for these experiments and finding out that you don't have to work on a skill for 10,000 hours to be an expert, but, please, don't say that 250 in England is an expert at table tennis. It is just a lie.
If you're in the top 250 out of 1000, that doesn't make you average. By definition it's well above average. Moreover, the 1000 ranked players do not represent the continuum of players overall. They are all significantly better than the actual average, which is why they are ranked.
Great spin off on the word average here. It makes you average at table tennis. But we are talking about being an "expert". So 250 in England does not make you an expert at table tennis. Also if you knew what you were talking about then you would know that if I want to get ranking ( just for the ranking sake) I would craft my schedule in a way so I play weak tournaments just to get ranking. Ranking and expertise correlation is very flawed. Ask any athlete about this and they will tell you that there are a lot of players that would play weak tournaments just to get ranking. They would be even top 50 in the country but it doesn't make them experts.
[1] http://tabletennisengland.co.uk/news/table-tennis-facts/
[2] http://tabletennisengland.co.uk/etta_website/annual_report/a...