if Ireland can create a business-friendly environment which improves the WHOLE country, why can't others?
From 1984 to 1992, the EU gave Ireland subsidies of 4 - 5.5% of GDP per year. The US currently raises 2.7% of GDP in federal corporation taxes. If someone were to give the US grants of about 5% of GDP, the US could afford to get rid of corporate taxes all together, and still have about $300 billion left over.
As to why other countries in Europe can't do the same, one disadvantage many of them have is that far from being net recipients of EU money, they have to make contributions. Somebody has to pay for Ireland and Spain and others to have all that free money.
There's no doubt Ireland used the money they were being given wisely, but it's much easier to cut tax rates when foreign governments are pouring money in to your treasury.