It's all relative, though. As Elizabeth pointed out, in a low-performing school 60% (or more) of first-third graders will be non-readers or close to it. RTI will not single out 60% of the population for Tier 2; only the most extreme cases will get that specialist help. For others it will be business as usual. Everything depends on local school conditions and populations.Right you are.
We occasionally get a student transferring in who has been classified LD, mild cognitive delay, or some other exceptionality. In some cases these students perform above average for our non-classified, general ed students. They get As and Bs without modifications or accommodations.
It serves as a reminder that "standards" are very flexible things and what is "low" or "high" depends on the school context.