That will always be a concern, even for a nonprofit. You need to keep the lights on, and people need to be paid. However, the trouble with VC funding is the expectation of scale. A VC won't be happy with a small organization that makes enough to pay its employees and sustain a small amount of growth. Unfortunately, that business requires large successes. So the founders and the investors can easily have very different goals.
VC funding is required if you want to build something massive, but isn't a great idea if the founders just want to build a sustainable but small business.
Companies like MailChimp and Atlassian are great examples of bootstrapped companies that became very successful. There are more.
Money is great to have at any stage of a company, and bootstrapped companies prefer to trade stability and time for the freedom of not having money (and those who only focus on it) control decisions.
You can build a great company with and without investment, but you can fail with either just as well.
And with VCs you have someone breathing down your neck to either grow fast or die fast. With bootstrap, you don’t have that pressure (and instead have the fuck we don’t have money to fund faster growth problem)
VC funding is required if you want to build something massive, but isn't a great idea if the founders just want to build a sustainable but small business.