But, for whatever reasons, schools aren't all teaching children to read effectively.
Clearly, there are reasons as to why this doesn't happen and just telling teachers that they should be following 'good practice' obviously isn't sufficient.
It's also not true to say that it's the teacher's fault that children struggle to learn to read. There are many developmental/educational reasons that children have difficulties in reading.
Children do also learn at different rates and have different learning styles, just the same as adults. In schools where there is a lot of mobility (about 10% of our Y1 child at our school have been in at least one other school already), there will definitely be gaps in children's learning.