I think I crossed the "more books than I could read in my lifetime" threshold back when Fictionwise was still in business. They had some amazing sales. And yes, those old reusable Kobo coupons were dangerous, too.
Given the size of my TBR mountain, I do buy few ebooks these days. I just keep up with a dozen or so favorite series/authors.
I've also spent more time listening to audiobooks than reading ebooks in the last few years, which isn't helping me get through that list any faster, either.