Ireland cannot do that. That’s literally the whole point of the EU (or specifically a single market)
Effectively - your hypothetical proposed ‘apple law’ would, at some point in the Irish law passing process, be found to be incompatible with their commitments to being in the EU, and I assume it would be then an unconstitutional law. The price of admittance to the EU is basically having this process and constitution.
Now - they could go ahead and do it anyway in which case the enforcement from the EU could range from anything to an angry letter to some large monetary penalty - as is the case with Hungary currently being withheld some funds.
I mean, isn't that exactly the case here though? Ireland's law said they could do this. The EU says that's wrong, and Ireland is seemingly getting a reward for doing something illegal that the EU didn't decide was illegal for almost 30 years?
Again, not disputing that this is legally accurate to how things work, but that definitely strikes me as an environment that a lot of businesses would find hard to work with. Other smaller startups I've worked with had Irish branches because it was a good way to hire devs and governments gave us some incentives. Finding out, potentially decades later, that the Irish government had screwed us over would be a lot more catastrophic than this fine will be to Apple.
They're not really getting a reward, because this makes them much less attractive for investment. Meaning less tax revenue in the wider and longer perspective.
I guess, but given this precedent, I doubt anywhere else in the EU is going to give a better deal, so all the companies where Ireland gave them illegal deals probably won't have any reason to move to Germany or Spain or Belgium. Ireland probably gets to keep their business and tax revenue going forward, as well as getting back taxes.
Does it make the EU/Ireland a little less attractive to foreign investment? Maybe. Was it worth the gamble in the end for Apple and Ireland - probably.
Effectively - your hypothetical proposed ‘apple law’ would, at some point in the Irish law passing process, be found to be incompatible with their commitments to being in the EU, and I assume it would be then an unconstitutional law. The price of admittance to the EU is basically having this process and constitution.
Now - they could go ahead and do it anyway in which case the enforcement from the EU could range from anything to an angry letter to some large monetary penalty - as is the case with Hungary currently being withheld some funds.