If you're a good enough writer with good ideas and you keep pitching persistently, you'll get traction soon enough. It's whether or not you're able to survive the unstable early goings that's the issue.
From my experience, if you're jumping into freelance writing without any savings (and starting from scratch with no connections with editors, no previous published pieces, etc.), it's hard to survive. Pitches take time (some editors might take months to reply). Writing/research takes time (you're essentially unpaid until your piece gets published). Even harder is the invoicing. You have to hound some publications to pay you (some take 45+ days to pay after your piece gets published). You really have to plan your pipeline well. When I tried doing it full-time for a bit, I planned ahead in terms of income (i.e. income from this month came from all the work I did in November). The moment you slow down or you stop pitching though, you know it's going to affect you in two months time.
Getting through the gates is tough but the hardest part is trying to find sustainable work that can pay your bills month to month. If you can develop relationships with editors (who consistently greenlight your pieces or give you regular assignments), that helps a lot. But, if you're starting out without any of that, the constant grind to find something regularly is stressful.
I still do it because I love it but I don't do it full-time anymore because I need to pay my bills.
I'm pretty sure being a freelancer journalist is not his main gig. Rather, this article was supposed to demonstrate one of the ways he was able to 'growth hack' his way into publications.
1. Check out Open Notebook - it really helped me see what my pitches were missing
2. A good pitch must have unique angle, be good storytelling in it's own right, answer 'so what' has lead to 'a ha...that explains why...'
3. You need to have lots of stories to pitch, be persistent and have a daily routine. Keeping track of each pitch in a spreadsheet is great for motivation.
To me it seems these are specific, not-obvious pieces of advice grounded in personal experience. Not at all fluff piece.