I tend to agree, with teams like India or SA, it has become more of psychological thing, despite having skills to perform good they underperform.

There is saying, "with confidence half the battle is won" — when big stakes are involves there are teams like Australia who are rather confident in their strength, look how they played against semis when 9 wickets were fallen against Pakistan, or look at Cummins and Maxwell's history making partnership in ODIWC against Afghanistan, they know how to perform under pressure, nothing is perfect and there are definitely exceptions in Australia's performances too but most of times they do perform good.

Indian team needs some mental coaching too aside from physical.