This has little to do with whether you are VC backed or bootstrapped.

The amount of effort to sustain yourself is going to be almost the same regardless of which category you are in. Either you have a category that is popular but will attract dozens of competitors no matter how small your niche is or you have a product that requires effort to market.

These days with so many no/low-code tools getting a product into market has never been easier. And that's both a positive and negative for bootstrappers.