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of people probably not, in the same way that Beethoven and Mozart are only really important to classical music fans who no longer represent the majority of music listeners.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.