I know several people that have gone down this path and a few who are doing it right now, the US seems outright vindictive against those that want to leave, a bit like an abusive spouse that can't imagine there is a life after them for you.
The problem in the Netherlands isn't so much expats who grew up in the US, but "accidental Americans" who were born in the US and left as small children. They are US citizens, but don't have an SSN, which Dutch banks require to comply with US law (and with pandemic-related embassy closures, obtaining one isn't necessarily easy).
Problem is that FATCA requires banks to actively send the US government personal information about its customers with US citizenship, while the GDPR forbids them from doing so without consent from their customers (https://americanexpatfinance.com/tax/item/632-eu-data-protec...)
But yes, accidental Americans definitely are a weird case. Some of them don’t even know they have US citizenship until the IRS sends them a message, or when, upon visiting the USA, border control requires them to show a US passport (https://en.wikipedia.org/wiki/Accidental_American#Awareness_...)
Regarding the difficulty of investing/borrowing outside the US: Non-US banks are required to report stuff to the US if they have US customers. So they might not want US customers because it's a hassle for them.