I agree with your overall point, however I disagree with the "just pick Rails and don't do SPA" part. For startups or any small team, the right approach is what

I agree with your overall point, however I disagree with the "just pick Rails and don't do SPA" part. For startups or any small team, the right approach is whatever boring technologies the team is comfortable with. If that is Rails, great! I personally don't know it so that would be a horrible choice for me. Likewise SPAs are comfortable and easy for me (aka boring), but a bad choice for someone else who isn't comfortable with them.