Lucky for us, otherwise instead of the free/open source software of the past decades we'd only have open core and similarly crippled offerings only :)

More seriously, the motivations behind open source projects and startups are completely different, it's just the end result being software makes them seem interchangeable. Open source software should be a public service and receive public funding ideally like most infrastructure that is essential for civilization.

In terms of putting food on the table, it doesn't really matter how you run it. If you're accepting donations or charging customers, you still gotta pay your taxes.