I think people focus too much on the shock value and miss the forest for the trees. The appeal, at its core, isn't really about the BDSM or the lifestyle. For a huge mainstream audience, it was a gateway into a genre they felt was forbidden to them. Before 'Fifty Shades,' a lot of women wouldn't be caught dead reading an erotic novel in public. This book, with its familiar romance novel skeleton, gave them permission. It wasn't just a book; it was a cultural event. You could talk about it with your friends, your coworkers, your book club, and it felt transgressive but safe because it was everywhere.
Where it succeeded was in making the fantasy of extreme power dynamics feel approachable. Christian Grey isn't a dom from a specialized, realistic BDSM novel; he's a moody billionaire with trauma who can be 'saved' by love. That's a classic romance trope wrapped in a new package. The reader gets the thrill of the 'taboo' without having to engage with the real complexities, rules, or ethics of a power-exchange relationship. For someone completely new to even the idea, it's a soft, sometimes problematic, introduction that sparks curiosity. The writing quality debate is endless, but its popularity was never about prose. It was about timing, accessibility, and fulfilling a fantasy of being so intensely desired that a man would build a whole contractual world around possessing you, while still maintaining the safety net of a traditional 'healing love' ending.
Honestly, a big part of its staying power in conversations is how divisive it is. You can't have a lukewarm opinion. People either found it liberating or deeply offensive, and that debate fuels more interest. It created a common reference point, for better or worse, that the entire romance and erotic fiction community had to grapple with.