Bootstrapping hasn't changed.. one test to being bootstrapped is: If they didn't get funding, would they run out of money and have to shut down?
It's not uncommon for a bootstrapped startup, which has baked 'making money' into the bread from the beginning, to accept funding to grow faster once they have a business model that's already making money. They already have a repeatable and scalable _business model_. Without funding, bootstrapped startups would continue to exist, and would most probably keep growing, though.