Not even going to lie, when I had my first child I was determined that he was going to be the child on "Ellen" who was fluently reading at 2 years old. I didn't purchase the "My Baby can Read" program, but I DID borrow it from my sister-in-law. I did however purchase the "Teach your Child to Read in 100 Easy Lessons." I was positive he was going to be a genius by age 4. I worked with him every night on alphabet recognition (which he didn't love doing by the way) and I pretty much drove him nuts. He WAS able to recognize all of his letters right before his 3rd birthday but then I had my second child and kind of backed off. The summer before he started pre-k I started back working with him a little bit again and I was shocked when I realized he no longer knew all of his letters nor was he even the least bit interested in learning them again. It took me awhile to realize that just memorizing the letters was doing nothing for him. If he wasn't actually doing something meaningful and learning their sounds, how they work together, etc. then he wasn't going to retain them.
As a pre-k teacher I had a hard time seeing the big picture. I thought the most important thing was making sure all of my students left my class knowing all of their letters, but when I moved to first grade it opened up my eyes A TON. There are some kids who can memorize all day long but if they are not phonologically aware, then those letters they memorized mean nothing.
Sight words are another thing I struggled with as a pre-k teacher. I thought it was awesome when I would have a parent come up and tell me their child had memorized 10 sight words, but if they aren't reading those words in text, they mean nothing to them and they are going to forget them. I think its so important to teach kids these words because they make up so much of our texts and they aren't able to sound them out, but I think its sad and pointless for Kindergarten teachers to have to make sure the child has these words memorized before they go on to first grade. Half of them get to first and they don't remember any of them because they were not developmentally ready.