It is maybe an exaggeration, I'm not completely sure, though. I perhaps should have used the term "professional standard" instead of "world class", though - as the latter term is too contentious...
In the 1960s, I don't think that all that many players could produce a professional standard recital of an hour's length or more, playing challenging pieces in the repertoire, such as a complete Bach Lute Suite, plus a piece by Rodrigo, a few lighter pieces (such as Catalan folksongs) and play to a level that we have become accustomed to - ie. not necessarily up there with JW, but a decent overall standard, minimal slips, a sense of interpretation that reflects the variety of music on offer and generally clean and professional playing.
The players that could do that in the 1960s were (as has been mentioned), Segovia, Bream, Williams, the Romeros, Diaz, Ida Presti, Lagoya, Yepes and perhaps a very few others that I have missed.
I read and have collected a number of BMG magazines from the 1960s. The same names predominate, and when a newcomer gives a recital somewhere,the results are not always satisfactory, if we are to judge the opinion of John Duarte - ie. some of the other players in London suffered from breakdowns in performance or major issues of interpretation or accuracy. Some people would question the validity of these reviews, as John Duarte has a reputation for being opinionated and sometimes biased in favour of his friends.
Now let's look at 2017. When I search for a challenging piece like the BWV 1006a, there are literally dozens of versions on offer, most of which are of the general standard that I mention above - ie. maybe not Bream or Williams, but clean, accurate and fully professional. Same goes for other pieces such as the Chaconne, and all the other pieces that were signs of a great player in the 1960s. I am extrapolating from Youtube of course, but if I can see perhaps 50 versions of 1006a that are professional, then there might be five times the number of players who can also play it to that level, but have never put it on Youtube. Same with any other traditionally challenging piece you can think of. I might be exaggerating by saying that there are 1,000 people who can give a thoroughly professional recital on classical guitar in the world in 2017, but who knows; it might be a lot more.
Incidentally, the fact that there were very few great players in the UK in the 1970s and a general interest in the classical guitar due to Bream, Williams and Segovia being featured on the TV, a few players (who I will not name, but let's say that they featured quite prominently in the Classical Guitar magazine as it became known), managed to make performance careers on the back of this popularity of the guitar. Some of those players had a valiant attempt at being performers, but many would get nowhere in today's climate of young virtuosi.
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