New York alone has 2 stock exchanges. I don’t think that companies being listed in London, Paris and Frankfurt (they generally are listed on several anyway) is the actual issue.
Especially these days the stock market is the very final stage anyway, most funding for growing tech companies is private funds, vc etc.
When Trump was invading Denmark, a huge % of Danes would've given a shit about sovereignty from the US. And that's the moment to pounce.