The exclusivity question really comes down to what you're optimizing for. Amazon's algorithms don't technically punish you for going wide, but they do reward exclusivity through KDP Select - you get access to Kindle Unlimited payments and can run promotional deals that boost visibility. If KU readers make up a huge chunk of your potential audience, staying exclusive might net you more money upfront. But here's the thing: you're locking yourself into one platform's ecosystem, and if Amazon's algorithm doesn't favor your book (which is luck-dependent), you've got nowhere else to lean on.
Going wide means you're splitting attention across multiple storefronts, which sounds diluted until you realize you're actually reaching different reader pools. Someone browsing Apple Books might never use Kindle. Libraries and indie bookstores often stock through IngramSpark. Draft2Digital has its own discovery tools. You lose the KU boost, sure, but you gain resilience - if one platform's algorithm is being weird that month, your other channels keep ticking over. Most authors who go wide report steadier, more predictable income even if the peaks aren't quite as high.
My honest take: if you're patient and don't mind slower initial growth, wide distribution tends to age better over a year or two. You also keep way more control - you can adjust pricing, run different promos on different platforms, experiment without being locked in. The exclusivity trap is real for authors chasing quick sales, but it's a trap. Start wide, gather data on where your readers actually are, and adjust from there. You can always go exclusive later if one platform's clearly dominating your sales anyway.