A little suspicious, but lacking hard evidence of trying to hurt competition, I choose to give Google the benefit of the doubt here.
I have had a ProtonMail account for a few years and the system keeps getting better. The one feature lacking, and keeping me from using it as a primary email service, is not being able to backup my emails locally. I think that is on their TODO list.
Code allowing external access (IMAP etc) to mailboxes that would allow you to download all your mail is in development now. Some IMAP clients (cough Microsoft cough) have "interesting" ways of interpreting/implementing the RFCs. So, it is taking somewhat longer than expected.
I have had a ProtonMail account for a few years and the system keeps getting better. The one feature lacking, and keeping me from using it as a primary email service, is not being able to backup my emails locally. I think that is on their TODO list.