Some truths in the infant industry argument:
Once a protective tariff is imposed, it is very difficult to remove, even after industrial maturity has been achieved.
It is very difficult to determine which industries will be capable of realizing comparative advantage potential and thus merit protection.
The argument generally is not valid for mature, industrialized countries.
There may be other ways of insulating a developing industry from cutthroat competition. Rather than adopt a protective tariff, the government could grant a subsidy to the industry.