Yeah, the external storage permissions are going away altogether according to https://developer.android.com/preview/privacy/scoped-storage - apps will no longer be able to get access to them.
Of course Google also prefers you to use content://-URIs instead anyway. Those do indeed have the advantage that the receiving app doesn't require any special permissions because it simply uses the permissions granted by the app sending that intent, but at the same time they also have a number of issues that Google chooses to ignore. I've ranted about some of those here (https://hg.mozilla.org/mozilla-central/rev/9175cafb84bd), and the most important in my view is that content://-URIs as currently implemented totally break opening of locally stored HTML files (https://issuetracker.google.com/issues/77406791) and other similar content that implicitly depends on more than the one file that can be transmitted through the content://-URI intent.