$100 -> corp. $90 -> expenses, $10 -> profit -> shareholders dist. $4 -> personal income tax.
In principal it's the same. Path 1 is easier to dodge, because what constitutes "expenses" is hard to define, but distributions are obvious. And the numbers don't have to add to 100. So reality looks more like:
$100 -> corp. $95 -> "expenses", $5 -> "profit". $2 -> corp tax, $8 -> shareholders dist.
vs
$100 -> corp. $95 -> "expenses", $5 -> "profit". $10 shareholders dist. $4 -> personal income tax.
And this is why you want to tax at the distribution level.
It is certainly plausible that a tax will provide no additional benefit. Microsoft is one of the great value creators of the late 20th/early 21st century. it is not immediately obvious why redirecting money away from the company is a good idea.
Were you deliberately or accidentally confusing the two?
It certainly isn't obvious that raising taxes is a net win. Experience to date is that a 100% tax rate is very bad, so logically there is a fair limit somewhere between 0% and 100% - ie, a specific fair rate that is not the word "more".
Certainly Ireland would like a slice of those billions of dollars - but if they try to take a big slice, Microsoft won't route the billions through Ireland. So it is a somewhat moot point in that specific case.
This confuses the issue - corporation tax has the opposite effect to this, because it only applies to profits. When profits are heavily taxed, there's a strong incentive to invest more money in R&D and longer-term internal investment (thereby avoiding corporation tax on that spending entirely) rather than reporting it as profit that's immediately distributed it to shareholders today.
There's interesting arguments about how this affects shareholders and whether it discourages external investment, but it's certainly not a drain on R&D.
To act like there's no additional benefit on taxing literally billions in revenue is absolutely nonsensical.