We received user feedback stating that some users do not prefer opening emails in "conversation thread view" and are looking for an option to turn it off. It’s simply a matter of preference, as they didn't indicate any issues while using the recently added "conversation thread view."
https://mail.google.com/mail/u/[email protected]/#inbox/FMfcgzQZTzWmrZldqcflcsRVGPfHBTTj