When I was in university fifty years ago I helped a number of students with their English. To my my surprise many of these students had very good marks in high school, but somewhere along the way basic spelling and grammar was not absorbed.
I saw a lack of basic skills with some of my students. I have never seen a study or even a thesis that explained why this is increasing. Academia is still undecided on the how and why. I believe it is a combination of things.
The ability to discipline was taken away or reduced by some boards. I am not talking about the strap. I am referring to detentions, essays or special assignments prepared by difficult students. Some boards consider this unfair. They feel teachers are singling out students, embarrassing and humiliating them.
Test methods (learning assessments) are difficult for staff to work within. The standard English test methods - multiple choice, short answers, and verbal assessments haven't really changed in 50 years or more.
We have to look at school boards and provincial governments. The policy of many boards was not to fail students. Some places suspended testing in favour of attendance rolls. Those who continually cut classes were labeled 'difficult' or 'special needs' and moved down the road.
The special needs area is a real rat's nest. Children with learning disabilities, autism, and other difficulties often go unrecognized and are passed on through the system. Some children are never assessed at all, coming out the end more dysfunctional than when they first went to school. It is less of a problem to have a 10 year old who cannot read than it is an 18 year old. How will these teenagers make out in the workplace?
Special needs students have to be assessed by doctors and educational specialists. The process takes time, can be expensive and is often frustrating for parents. From 3 to 18, minors are placed on waiting lists for learning assessments, funding, medical diagnosis, disability assessments, educational assistants, special help programs. The list goes on. The process is daunting for parents whose children are not learning at the rate that falls within the bell curve.
It is a windy, difficult path from Kindergarten to the finish of formal schooling, whatever that may be. Some parents don't care. Others complain too much.
Principals are responsible for their schools budget. The yearly amount is fixed. They are constantly juggling to find the money to pay EAs, programs and tech for the classrooms.
I have a lot of respect for people whose job involves assessment and special programs. They have remarkable patience and thick skins.