A point that you're forgetting, which is extremely important for a lot of people, is access to a public library's collection of ebooks. In Canada, Kobo is overwhelmingly capable of connecting with a public library, while Kindle cannot. It is, in my experience, the number one reason why people around me choose a Kobo over a Kindle.
I don’t live in Canada and so I wasn’t aware of that because Kindle works in US library systems.
My guess is that it doesn’t work in Canada because Kobo was a Canadian company before it was acquired and because Kobo’s owner used to own Overdrive (before it sold it to private equity a few years ago), but I could be wrong.
Obviously, if a device doesn’t work with the services you engage with, it’s probably not the service for you. But since Kindle does work with many, many library systems (and its arrangements with libraries predates Kobo’s existence), I think that’s more regional edge case and not a blanket reason to use one over the other, which is what OP was saying.
Kindles only work with libraries in the U.S. Nowhere else. That's the regional edge case. Overdrive also supported ePubs before Kindle including the original Kobo back in 2010 although you had to go through the whole Adobe Digital Editions rigamarole.
TIL. And yes, that’s definitely a larger edge case but I would still posit that for many users who are buying into an ecosystem, Kindle is going to be the most portable. But that’s an important distinction for anyone who wants to check books out from their local library.
I don't understand how you think Kindle is more portable. Kobo works with ePubs and they support Adobe's DRM which is used in a lot of stores. There's nothing tying you to Kobo's store and almost every ebook store that sells epubs is compatible.
Meanwhile Amazon has been constantly messing with their proprietary format, DRM etc. Any book bought outside their store also almost always needs conversion too.
I mean, I’ve been using e-readers since 2006 or so and very rarely get books from the library. Honestly, they usually don’t have the books I want to read or if they do, there is a many week wait. At that point, I just buy the book myself or I’ll find it another way.
I’m not going to pretend that’s the same for everyone, but I’m equally not going to pretend every person who has an e-reader is constantly getting stuff from the public library.