Many people, especially in physically demanding jobs, which often coincide with low education, simply never got into books. They are simply not in their radar as a form of education or entertainment.
Which is kind of understandable. If day job and daily life already fill your time completely, you may just want to be numb in front of a TV.
Also, don't forget that many younger people don't read books that much, simply because they consume different media.
And a final note: look at what the bestselling books are. Cheap romance, crime and thriller crap. Reading those is intellectually nil. You might as well watch the daily soap opera.
Between 20-25% of the European population is functionally illiterate. In other words: at least one citizen in five does not have the reading and writing skills they need for functioning in society, with all its consequences for education, employment, health care, welfare, social integration and political participation. ‘More than 73 million adults in the EU… do not have sufficient literacy levels to cope with the daily requirements of personal, social, and economic life’
I could not find info on how they get to 20-25% functionally illiterate. That seems way too high. 17% for Germany.
Do you know how they define illiterate?
"Functionally Illiterate" doesn't mean that those people can't read or write. But it does mean that they don't understand what the words even mean.
Or in other words. Just because you know how to do something doesn't mean that you understand how it works. Lots of people drive cars or use computers but many of them have no real understanding on how they actually work.