The EU doesn't have general legislative competence for tax: it's reserved to the member States. To change this would (IIRC) require a new treaty, and the perceived loss of sovereignty would go down like a lead balloon with many of the governments - so that won't happen at least in the short term.

Because to do that all the EU contries would need to agree. How do you go about convincing Ireland to vote for something like that?

Uh, money? Seems like an obvious one.

Lobbying.