Says right in the article you linked:
ROSALSKY: Warren argues her proposal learns from the failures in Europe. She told us in an email, quote, "I specifically designed this proposal to account for lessons learned from wealth taxes in other countries," unquote. Unlike in the European Union, it's hard for Americans to freely move to another country or state and escape national taxes. On top of that, the Warren plan imposes an exit tax, which would confiscate 40 percent of a person's wealth over $50 million if they renounce their citizenship. But the plan's key difference, Zucman says...
ZUCMAN: It's only for people who have more than $50 million in wealth - ultra-wealthy individuals.
ROSALSKY: In Europe, the tax affected a much bigger percentage of the population. Zucman believes that helped the rich lobby for all sorts of exemptions on business assets and pensions and artwork. It made for a leaky bucket.
ZUCMAN: That's what killed, basically, the European wealth taxes - these exemptions.
ROSALSKY: But Warren says that her proposal, which has no exemptions, will play out differently in the United States. Greg Rosalsky, NPR News.
So it's not like they haven't looked at what has/has not worked in Europe. I'm not saying it will definitely work in the US, but the plan was not decided on in a bubble at least.