I’ll add my opinion to this thread as I was born in Czech Republic, but grew up in Canada since I was a little kid. I coached in Prague for 7 years from 2011-2018.
The technique aspect I would say is definitely true, as I noticed it’s a big part of the training there (from top coaches) along with footwork and balance. It has to be as the majority of courts in the country are red clay including indoors. In the winter they just bubble the clay courts, and in my opinion it plays like ass under a bubble, but it is what it is and you better know how to move and technique needs to be solid.
There are tons, and I mean tons of mediocre coaches in the country. Charging very little for a lesson, come on court with horrible balls, don’t shut their mouth the whole lesson and are basically ball feeders. No where is it perfect. However, one of the biggest differences between Czech Republic and tennis in Canada for example, as I can compare those two really well, is that in CZ there’s an environment and culture around tennis and especially competitive tennis. Be it high quality league matches between clubs, lots of tournament, competition between players, pride etc. One of the biggest differences I found in regards to culture was that former players (top 500, 600, 700 etc) become coaches for various reasons and can then better teach the next generation of players, especially through experience of their own which is severely lacking in a country such as Canada. I mention various reasons for them to become coaches as it can be anything from a lack of other jobs or just not being able to have a corporate job but instead can make a decent living coaching tennis. The culture in Canada is nowhere near this, nor is the environment at tennis clubs. It’s all about recreational tennis and people here do not understand what it takes or what actually is high level coaching, training and high performance junior tennis. I swear sometimes people, especially tennis parents, have no clue what a good quality coach actually is and get BS’ed by what I like to call used car salesman. I found that in CZ its a little bit different and because its a small country and with a large tennis population, reputations play a big part and its not difficult to find a good coach who has produced results.
Why are Czechs producing good players now? Who really knows as I didn’t find anything out of the ordinary compared to my time in Germany or Spain. Spain definitely has a ton of great coaching methodologies in RPT Europe (drills, mindset, fitness etc) so who knows. I think it also goes back to a bit of the Slavic and Eastern European (for the Czechs in here I know you’ll say “NO WE ARE CENTRAL EUROPE!!” Haha) mentality, parents being more tough on their kids, kids understanding the sacrifices their family is making and so on.