Thanks for this.
Note that TTS is still a staple in the Kindle app on Fire tablets for some reason. And of course Alexa (wherever you find 'her') is happy to read out most of your Kindle books. I have not seen anybody loudly complaining about this, even though these 'compete with audiobooks' in the same way that supposedly Kindles with TTS did.
Kindles do support TTS, in China, on a very limited basis:
https://www.mobileread.com/forums/sh...d.php?t=348449. It's not clear why they did this, given they are exiting the market there. It does not seem to portend broader support in other markets, but I would not mind if they turned on the switch for other markets.
I well understand the difference between TTS and screen readers, and there's not that much overlap between use cases. Speak Screen on iOS is the nearest equivalent to TTS, but it is (as the name implies) still an accessibility feature in the end. It's nice that Kindle app implements it in such a way that it support continuous reading, and I do use it occasionally.
Google Play Books does not have TTS. It doesn't surprise me that it doesn't have good TalkBack support. They are in the business of selling ads. Kindle app does support TalkBack well, or did the last time I tried it.
I like TTS enough that I got a PocketBook Era. It works very well, and I think the voices are Ivona (owned by Amazon).