They would be if the revenue from search engine deals fell away. They've been experimenting with different, user-respecting sources of funding (and still are), but also have to face with enormous amounts of backlash every time they do, so finding alternative funding is not as simple as you make it out to be.

> Are they that cash strapped?

It's more the opposite. They get a huge amount of money from Google. It's pretty hard to replace. E.g. see https://en.wikipedia.org/wiki/Mozilla_Foundation#Financing for a mention + source of 300 MUSD per year.