Sure. But I'm pretty sure Ezra Klein means "under current law"; of course the law could change such that this is not the case any more.
I think you're reading a stronger argument into the original article than is present. He's not arguing that Roberts is constitutionally guaranteed this power, or anything of the sort. Just that under current law, he has this power, and under current law, it's a lifetime appointment since the position that grants such power, Chief Justice of the Supreme Court, is also a lifetime appointment.
Maybe he does, but since Congress can't restrain the Supreme Court in other ways (eg by taking away the power of judicial review), omitting the caveat in this case is a serious oversight that is going to result in many, if not most, readers getting entirely the wrong impression.
Journalists who write on legal topics have an ethical obligation to provide proper context to their readers, few of whom have any legal training. Frankly, I think that journalists ought to have a JD themselves before covering these topics, in much the same way tht science journalists ought to have a BS.
I think you're reading a stronger argument into the original article than is present. He's not arguing that Roberts is constitutionally guaranteed this power, or anything of the sort. Just that under current law, he has this power, and under current law, it's a lifetime appointment since the position that grants such power, Chief Justice of the Supreme Court, is also a lifetime appointment.