It depends on the level at which the reading is done. For very young children, the technicalities of reading, spelling and so on may be important, but I think they should be introduced to reading for pleasure as soon as possible, even if they are reading undemanding books below their nominal reading age.
But I don't see why reading for pleasure can't sit side by side with deeper analysis of specified works.
I never stopped reading for pleasure, but when I was doing A-level English not only were the teacher's requirements much more demanding but I don't think that at that time I would have dreamt of tackling, say, Chaucer without quite bit of help and guidance, But once I'd been forced to do the set book of Chaucer, I went on to read with great interest other bits of Chaucer and also to try Piers Ploughman, Pearl, Sir Gawain and the Green Knight and Le Morte d'Arthur on my own. It was harder doing it without a teacher, and I can't say I have great expertise in Middle English, but the experience of being made to study some Chaucer opened up a great deal of literature to me that I probably would never have accessed unless in modern translation.
Reading works in the original language adds an extra dimension to them. I wish I had been able to learn Ancient Greek when I was at school, because I would love to read the great Greek classics without translation.