What good PR is there in being know as scraping other EU countries of it’s tax dollars? Ireland would still had good tech employment as the only sizable English speaking country left in the EU.

Ireland has a low tax rate, other countries are free to lower theirs. This is not a 'race to the bottom' for the simple reason that people will vote out a government that gives too much to multinationals at the expense of the people. Low corporate taxes are extremely popular in Ireland, so it's obviously working there.

On the other hand, if you're referring to where taxation occurs, then other countries are free to change their rules to make sure taxation occurs where they want it.

Simply put, Ireland is successfully out-competing high tax, high waste countries (like most of the rest of the EU), and they are sore losers about it.