Vance v Terrazas had the opposite effect, voiding laws that provided for automatic loss of citizenship, and establishing that citizenship could only be lost if that was the citizen's intent, whilst retaining some wriggle rom in the form of acknowledging that actions other than signing a form renouncing citizenship might form the basis for demonstration of intent.

Richards was a narrower case and in any event has been superseded by changes in both US and foreign policy. Canada no longer requires passport applicants with other nationalities to sign a renunciation statement, and US policy no longer seeks to use such statements as a basis for denying a U.S. passport.

So whilst in theory there are still other means to get rid of your US citizenship that don't involve a lengthy bureaucratic process and a 2500 dollar fee, in practice it's unlikely to happen unless you show up on YouTube beheading a western journalist whilst shouting "Allahu Akbar," in which case you're probably likely to lose more than your passport, and they may decide to let you retain your citizenship for the duration of your life without parole sentence in any event. Given the choice, most people, I believe would go for for the fee and form option, so whilst you are correct in the theoretical legal sense, in practice there is no alternative path to losing your citizenship other than renunciation.