It all gets terribly murky very quickly. For example, we often claim one of our strengths is that we have a highly educated workforce - but this is circular; people take this path because they know there's good work at the other end of it. If we ripped out those MNCs, that highly educated workforce would vanish quicker than you can say J1.
There are other benefits to being in Ireland. We have a common-law legal system, which is more familiar to Americans than most continental systems. We mostly speak the same language. We're still in the EU, etc.
How much of a presence you need here to make it work, I'm not entirely clear on. But it does seem apparent to me that once you're maintaining a presence anyway, it knocks down the largest barrier to actually building on that presence.
For example, it's widely assumed that Apple are only here for the taxes. I think they were originally here as a low-cost entry into Europe. But however it's worked out, last I heard Cork was the only factory (or perhaps the only factory outside the US?) that Apple actually owns. I'm typing this on an iMac that was assembled in Ireland. Apple are a success story - even more so because they're in Cork, rather than everything but everything being built in the Dublin bubble (a separate but very real issue).
And taxes aren't the only incentives; I used to work in a building that was sold to DEC (by the Irish Development Agency) for 1 Irish pound - which would have been $1.45 when we left the pound in the 90s. Not sure what it was worth when we sold the building, but .. probably still a close approximation of pocket change. And again, it paid off - it sounds like a story of us "bending over for the yanks", but the site passed through DEC to Gateway to HP to HPE. What started off as a factory for Digital is now stuffed full of developers for HPE. We haven't just had decades of employment out of that deal, but the value of that employment has been constantly rising. Ireland's modernisation is the result of thousands of such stories.
But as for a race to the bottom, it sort of is. Factories are being built in Central & Eastern Europe today, for most the same reason they were being built in Ireland in the 70s and 80s. Just as we were trying to undercut France, Germany & the UK to get our leg up - they're trying to undercut us to do the same. I do think there's a point where we need to "pivot" to actually acting like a modern economy, and let other nations take our rung on the ladder - instead of having to lay claim to one even further down.
I do agree with the idea that our modern economy shouldn't still depend on being a pseudo tax-haven. I just don't think "hit them as hard as we can" is the right solution, especially while we're still riding on their backs.
(To make this look a little less rant, I'll cheer it up with a fine example of a PDP that does not say Maynard on the front)
https://en.wikipedia.org/wiki/DECtape#/media/File:DECTape_un...
https://www.flickr.com/photos/32614724@N06/3045263847