> Greek homeowners would be left with unpayable euro mortgages

Just fyi, Hungary had a ton of homeowners with loans in EUR and CHF and when the HUF collapsed the rates became untenable and the government just said "eh, fuck the banks, let's keep the previous exchange rate". The banks survived too.

It's a hard political decision but not an impossible one.

(Disclosure: I deeply disliked that government for other reasons and didn't have a loan, it was just interesting to see populism in action without obvious downsides materializing)