So if I get your emails every week and I open them all at least once, but if I rarely ever click through, that should tell you something. I am an "aspirational fan" - something about your brand resonates with me, even if I haven't yet made a purchase. This holds true whether you're Pottery Barn, Restoration Hardware, Tesla, Harley-Davidson or the Humane Society.
We already know that emails drive offline purchasing and that most people will not subscribe to multiple emails in a vertical. (If I'm receiving emails from The Home Depot, I'm not subscribed to Lowes or TrueValue emails.)
And yet (to pick on Pottery Barn), there's nothing much to suggest that the email I receive is tailored for me. It feels like a batch-and-blast. It could be that they don't have enough click data or purchasing data to customize the email, but it doesn't feel like that's the case. (Sadly, this is often the case - email is successful enough that it's hard to justify, or get the headcount, to do more specific targeting.)
But if I'm continuing to engage by receiving and opening your email, I'm the perfect person to do experiments on. Offer smaller items with lower price points. Try to get me to engage with you on social media. Run a contest where I could win something off my wish list if I make a wish list. (And my chances increase if I get others to make wish lists.) Big, bold experiments to try to get me to engage deeper so that someday I do become a regular customer, a deeply engaged customer, a brand ambassador.