The one thing that hasn’t changed with the word is that content is still king. It governs almost everything in terms of audience and reach, though it’s true that marketing (or promotion, brand, or whatever other stand-in term it is you cling to) plays a part too. The maxim of Quality over Quantity is still true, but when everyone is a content creator in some way, the saying becomes more of a tendency than a fixed rule.
Luck plays a big part in being noticed. That’s been true for a long time, and the world doesn’t owe anyone a shot. Fifteen minutes? Most won’t get offered fifteen seconds, no matter how good or bad they are.
If you do want to make it, you have to get noticed. Much as might happen amongst employees, it’s the noisy bee that’s seen as busiest. The quiet one that flies in, does the job well, and leaves? Well they can’t be working that hard, right? Even if the momentary spur is brilliant, it’s soon forgotten.
Just as there’s no point having the best story in the world in your head when you’re unable to write it or present it in a way that’ll make either audiences or publishers sit up and pay attention, there’s no point having the best content around if you can’t get it noticed.
This doesn’t mean quantity is better than quality. There’s still no excuse for poor quality, but if you’re not creating enough content, if your name isn’t out there enough that someone says “Hey, it’s so-and-so again. I might take a look at what they’re doing” then you’re going to be lost in a sea of noise.
Your potential audience doesn’t know that your content is good. They need as many chances to find it as you can give.
Quantity still matters. How much of it you want to produce is still up to you.