I am not sure, to go back on something that piggywaspushed said, that it is all about not reading.
I have two readers - and my younger one (finishing Year 8) is more likely to be found with her head in a book than not (as in, I come in and she hasn't done anything she is supposed to, because the first thing she did on getting home from school was hit the sofa with a book). She can easily spend most of the weekend reading. Yes she does use her phone to talk to her friends and play games, but there is a lot of reading going on. And randomly at least some sort of children's classics are picked up - I came in to find her reading Peter Pan yesterday, we missed it at an earlier stage. And she borrowed a version of Les Mis from the library last week. She also does what I used to do, which is read at every level (reread the most basic children's books up to whatever is lying around, including books being read by adults).
And yet I cannot see her doing A Level English - because while she generally scores reasonably highly on the creative writing, and has a good knowledge of vocabulary - she bombs the PEE paragraphs - just really struggles to get what they want from her, finds them formulatic, and has been put in set 3 English as a result (she is set one Maths & Science). So she concludes that she is "bad" at English and "good at STEM.
My older one, just finishing his GCSEs, whilst also a reader, has tended to focus on young adult fiction (which I loathe as a major component of the diet). The GCSEs in combination with some of my own reading and those of his friends has in fact pushed him into reading more widely and deeply, and he discovered that he loved the poetry they did (War & Conflict) - or at least most of them, and feels that he now has some idea of what makes for better literature (he has just gone and tidied up his room post GCSEs and cleared out the young adult fiction to make room for other things). But as he is taking A levels in STEM subjects, he is now feeling he needs to "read around" non fiction STEM related books in preparation for university. Although he ended up enjoying the English literature he was presented with, he did not enjoy the quote memorising, and he found it much easier to get top marks in STEM. If you really, really knew your subject and studied hard he felt you had a high probability of good marks in STEM. In English the marking always felt uncertain, who knows whether what you said would appeal, and he also struggled all the way through with PEE paragraphs and the "right" way to write an essay to get the marks wanted. For somebody who has some issue with spelling (he spells like a dyslexic, just doesn't read like one, and we spent much of primary school battling with the spelling, to limited avail), the SPAG marks were a killer. So while he doesn't need to be able to spell to read widely, he does to consider taking it as a subject. So while he thinks he is going to miss it, there is no way he could consider it for A level.