No, not really. "Importance" is a rough proxy for legacy and influence. This is why one can say without any trace of subjectivism that Shakespeare is the most important writer of the English language, or Kafka the most important writer in modern German, etc. Maybe this is slightly less rigorous in the case of '2666' which is still a relatively young work, but it is widely hailed as a landmark novel.
Was Shakespeare a great writer? In my opinion, yes. Is he still influential? To a lot of people yes, but to a growing amount of people probably not, in the same way that Beethoven and Mozart are only really important to classical music fans who no longer represent the majority of music listeners. Your average clubber probably doesn’t give a fuck. You could argue that the professors could get extra weighting for having dedicated their lives to studying literature but who’s to say that social factors aren’t at play and that people who become professors of literature become professors of literature because they conform well to the standard viewpoints and social norms circulating in those circles? Birds of a feather flock together.
Literature is not like science - there are no hard and fast rules where you can be outed as a bad literature professor the way a bad scientist can be identified after publishing papers which can be later demonstrably disproved by experiments. Judging a book is a personal evaluation of a piece of art.
Importance is subjective depending on the individual and the group and it is also temporal and fleeting in nature.
To quote Shelley:
I met a traveller from an antique land,
Who said—“Two vast and trunkless legs of stone
Stand in the desert. . . . Near them, on the sand,
Half sunk a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them, and the heart that fed;
And on the pedestal, these words appear:
My name is Ozymandias, King of Kings;
Look on my Works, ye Mighty, and despair!
Nothing beside remains. Round the decay
Of that colossal Wreck, boundless and bare
The lone and level sands stretch far away.”
A very important man that Ozymandias, in his time. Not anymore.
The argument is also flawed because favourite is not important. If you asked someone what their favourite food was they may say Chinese takeout. If you asked them what their most important food was, they may say Sunday dinner because it reminds them of their deceased mother. There is a significant difference between the two, one is a personal preference but the other could compromise a bigger part of one’s identity.
Here’s a thought experiment:
Which book is more important? The book that the most influential man in the world considers the most important but which nobody else has read? Or the book dismissed by all elites but that is the most important book to the least influential billion people on the planet?