A foreign coach is not always the answer
In countries where the sport culture is strong and the supporting infrastructure is well established hiring a foreign sports coach might be a good way of improving elite athlete performance. This is especially true when hiring coaches from countries that seem to have the secret recipe for high performance in certain sports. It wasn't too long ago when every country wanted a Brazilian football coach, a Romanian gymnastics coach, or a Russian weightlifting guru.
Nowadays global coaching performance has leveled off and the demand for foreign coaches is found mostly in countries where the sport culture and infrastructure is still developing. This mix of foreign coaches and developing sport cultures doesn't always have the result that the hiring country hopes for. Here are some reasons why this doesn't always work:
Coaching success depends on more than simple technical expertise. Invisible things that affect interactions between athletes, coaches, parents, officials, and other sport administrators can really make a difference. People skills may determine success or failure.
Is the coach trusted by the athletes? Without trust that athlete/coach relationship won't thrive. There have been many instances where successful coaches and top athletes simply did not work well together. It's hard to predict what the relationship between an athlete and a newly hired coach will eventually become and when you add a radical difference in culture to the mix the result is even more unpredictable.
Is there a sport infrastructure that supports the coach?
The quality of coaching in a country depends directly on the system of facilities, competitions, participation, and governance of the sport. It also depends indirectly on larger aspects of a society such as the economy, education, and government. All countries have varying degrees of social infrastructure that either support sport or don't. A successful coach is a product of this infrastructure. Take a great coach out of the system where he thrives and results may not be as remarkable.
Removing a coach from his home environment where he achieved success diminishes his effectiveness. It would be similar to having a modern-day smartphone in the 1980s; a remarkable piece of equipment but not very useful since the environment in which it works hadn't been invented yet.
This is why bringing in foreign coaches has always been a gamble. Without a comprehensive sport infrastructure the coach's effectiveness is limited. Ironically if the sport infrastructure is well developed then there may not be any need for foreign coaches in the first place because the environment will have already produced not only good athletes but also good coaches.
Foreign coaches, no matter how good, are not a guaranteed pathway to better sport performance. Rather than pining after coaches from successful sport countries national governing bodies should first try to understand the systems that created them. In countries with nascent sport cultures it's usually the infrastructure that is lacking not the personnel. Bringing in coaches from other countries makes it less likely that a country will develop their own cadre of talented coaches.
Foreign coaches can have a role to play in developing sport cultures but it is important for all involved to understand how that role is to be defined and how results are to be measured.