[nonameiguess]

The reason it's shallow is this is directly addressed by the content of the article. The author starts out the essay by giving all of the reasons we have to believe that our relationships with pets and other humans are mutual, i.e. closeness in evolutionary distance, the fact that we're all social creatures that form bonds within our own species that are clearly advantageous to us and friendship makes sense from that standpoint. It then contrasts that with a traditional naive view of octopuses as loners that either mate or kill each other when they meet in the wild, giving reason to doubt that they would form friendships with humans.

It then goes on to complicate that narrative, claiming that more recent discoveries indicate many species of octopus are, in fact, social creatures, and older understanding of them was likely due to insufficient observation and the fact they hide themselves so well.

It's quite an in-depth essay with a lot of information in it that addresses this exact question with nuance, research, anecdotes, from every side of every possible answer. It deserves better than a pithy response implying the author never thought to just ask the reverse question. He definitely already thought of this.