Yeah I never thought of anything backing bitcoin.
Only it's own technology and hype has fueled it thus far.
And has made it what it is until now.
Maybe the author speaks about time backing up bitcoins different from your view. The author possibly observed that the longer bitcoin is in the market its price has doubled. Another meaning possibly that time itself is the witness on the stability and the price inflation of bitcoins.
But I'm not setting aside your opinion since it is also a possibility that I have misinterpreted the idea that the author implies.