Great question — answering as the UphillTech team:
Great question, however hard it may be to provide a satisfactory answer to... :) I cannot give you statistics on homegrown vs foreign managers in national teams, but I just want to point out that there are lots of homegrown managers that do not do well at all, likewise foreign managers that do wonders. Let's look at some examples: Brazil won all their World Cup titles with Brazilian managers, even when they came 2nd or 3rd they had Brazilian managers. For that matter, I don't know if they ever had a foreign manager, and it appears as if it hasn't been much of a problem for them. Italy, much like Brazil, won all their titles, got 2nd and 3rd place finishes in the World Cup with Italian...
Full answer by posdef: https://sports.stackexchange.com/a/953 (CC BY-SA 3.0).
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