> Ability to read does not correlate interest to read or more importantly ability to understand

It may not correlate, but it does condition.

That is to say, one can have 100% interest in reading, but if you can only read 1% of published works, you will be just as good as someone who is a perfect reader but only 1% interested in reading.

Similarly, with comprehension.

Reading well is necessary to be interested enough to read more and to comprehend.