I learned to read with the Dick and Jane books and it gave me a great sense of accomplishment to have memorized the entire wordlist at the back of the book. Our teachers supplemented this with phonics, sounding out word groups, there was a spelling book that had a lot of phonics in it, and we did round robin reading thru the fourth grade. Fifth and six grades were private readings from color-coded cards and answering questions on the content.
Yes, some can do this. Takes good memory and discipline. But the key event, which kids don’t even think about, is that they are figuring out the phonics inside all the words. So they move pass sight-words. Soon they can read all the words.
But many kids are not verbally clever and they remain permanently at that point where they have memorized a few hundred sight-words. That’s it. These people are called functional illiterates.