I think that you are overestimating the size of the audience of people who have nerd rage over whatever we’re pissed off at Apple about or have meaningful concerns about government surveillance.
They’d be better off focusing on making a better user experience instead of E2EE drama.
The size of the audience may be small indeed. But Apple users on average have deep pockets and are willing to spend. A quick search suggests Apple users spend >2x what Android users spend. No data yet on what Apple users spend compared to Linux users. It's part of the reason "but 5% marketshare!" was never a good argument against the rise of Mac/iPhone.
The moms and kids dropping 1000$ on candy crush every month are not going to switch off apple. The big spenders in apples echo system are not the tech literate. The tech literate normally cost way more to maintained from a client perspective. Also they are allot more concerned over costs with regards to space as seen by allot of comments on this page talking about how expensive storage is.
They’d be better off focusing on making a better user experience instead of E2EE drama.