> Profit goes out of the country, reducing investment and rich UK people to invest in new UK companies.

Rich foreigners are happy to invest in the UK. See eg Deepmind itself, which was bought by Google.

> [...] so our labour enriches other countries while our country gets poorer.

Foreign investment is usually seen as a good thing. Especially foreign direct investment.

And: why do you care so much what passports these rich people hold?