A Change in the Air for Naps

I remember when Drew was two and decided he didn't want to take a nap anymore.  We had a gate on his room so he still had to stay in his room for a couple hours and he would eventually fall asleep after looking at books for awhile.  Then after he turned three he was completely done with any nap attempt.  Cade has now also gotten to that point.  Sometimes he'll get out of his bed and then lie under it.  I'm not really sure what that's about but he has taken multiple naps on the floor in the last few weeks.  Most other times, he makes his way down to the playroom.  If Drew is resting with his stuffed animals in the guest room, Cade will just play by himself.  Otherwise the two of them play or read books.  I'm not ready for Cade to go from 3 hour naps to nothing.  He's not even 2.5 yet.  I used to work with people that would talk about how even their kindergartner still took naps on the weekends.  I don't understand that at all.  Why do my kids want to quit when they are two?