Your argument is, essentially, an "everything else being equal" one. But it won't be. Company structures, trusts etc will be restructured to best deal with whatever the new laws state. As they do with the current laws.
Of course, the corollary is that she's also well aware that it won't raise anything like the money that's suggested but, from her perspective, that's not a problem either. In fact, the opposite. Bringing in a wealth tax that the wealthy avoid is probably close to ideal: deliver on your promise and still have the bogeyman. Result.
What I think is genuinely interesting is that the whole idea of a wealth tax is now considered to be electorally sensible. That's a huge change from a decade or so ago and, potentially, makes way for much more radical policies to be touted without the usual faux-shocked response.
Btw it takes about 8 years to reduce the wealth to 60%. That will do the balance and you can have another president by then. It is not forever.