creative writing - Is it true that a great cover is enough to sell many copies of your book

I've come across podcasts and internet articles about self-publishing in which they basically say that books with fantastic covers and interesting blurbs tend to sell lots of copies even if the actual writing is substandard.

And there is also this article I recently stumbled upon that blatantly outlines in the quoted text that some people buy books based on the cover alone (and perhaps a quick cursory glance at the blurb):

The general evaluation process goes something like this:

Click on book because of cool, relevant cover.

Scroll down and read the tagline/first few words of the blurb.

Leave, click buy, or read a few reviews.


OR

Leave, click buy, or read the sample.

OR

Leave or click buy.

In other words, a strong cover and blurb can sell your book.

My question is: Is it really true that many ebook buyers are silly enough to purchase a book simply because of its cover (and blurb) without first sampling the actual writing inside the book? I find this hard to believe.But yet this is the impression or outright assertion that is often made when I hear people talk about the enormous importance of great covers for selling books.