It IS possible to get lucky on content aggregation sites without any magic. I've had this happen for me in several places – HN, Reddit, Medium. But it's very hit and miss. You can post something great and have it totally miss 9 out of 10 times. Most people aren't interested in sifting through the new stuff – they just want to engage with whatever's already popular. If even 5-10% of a community was committed to rigorously assessing new submissions, then quality would rise to the top – but most people tend to just upvote whatever is already on the up-and-up.
This "Mathew effect" is the case with a lot of things – book deals and record deals, for instance. Unknown artists occasionally do get their big breaks by being in the right place at the right time. But if you're managing one (even if it's yourself), it makes sense to improve your odds by being systematic, and yes, basically cosying up to the gatekeepers whoever they are.