No comic produced within the last ten years will ever sell for anything within a hundred miles of 2.1 million. Occasionally a collector might hit big with a Chew #1 but all in all, 99.999999% of comic collections featuring comics produced since 1990 aren't worth (incl inflation/opportunity cost) what they paid for them.
Also, the paper magazine has the same content as the digital magazine so the idea that the date produced of the content matters in one medium vs another is just silly.
I am also bemused the author didn't include the two biggest reasons to read paper
1) Nobody can take back your physical copy unlike digital where the publisher/vendor can likely decide to erase/edit or disable access to your purchased content anytime they like.
2) You can lend or give away a physical copy.