The lesson of Levison is that privacy assurances by email service providers are not necessarily trustworthy. Levison balked, but most wouldn't want to shut down their businesses.
For now the best bet is either to self host (it's not that hard, especially for most folks reading this) or to use something like ProtonMail where the content can't be routinely exfiltrated and the provider can't give the inbox keys to any third party.
For now the best bet is either to self host (it's not that hard, especially for most folks reading this) or to use something like ProtonMail where the content can't be routinely exfiltrated and the provider can't give the inbox keys to any third party.