It's easy for people to talk about their ambitions and just think that they want to do this and that. But that doesn't mean they will actually do it. People will only do something when the reward is greater than the risk. People face different risk and reward in different time and when they are in different position. You may ask why didn't Fernandez add more quads to his sp and why didn't Chan add more 3A or quads before. When a skater has no major title and is the underdog, he would not hesitate to upgrade his layout and take more risk because his has nothing to lose. But when a skater reaches the top and is considered one of the best skaters and the one to beat, the expectation he faces is much bigger. The public expects him to give flawless or near flawless performances in the future. He has a lot to lose if he gives a sub-par performance, i.e. he will lose his momentum, reputation and the chance to win in the future. (Skaters become more inconsistent when they try more risky elements. Nobody is guaranteed to be consistent in competition as soon as they try a new jump no matter how consistent their jumps are in practice. They usually have to fall many times before they become consistent in competitions.) When skaters reach the top, they become more passive and conservative in taking risk. You can look all the champions in the past, as soon as they reach the top, they don't take more risk any more (they are not serious about it even if they do try some risky elements) unless they have strong close rivals to challenge them. It's not that they are not capable of doing more technically, but they have too much to lose and they become more conservative because they become afraid of losing when gold is theirs to lose.
Hanyu is not superman. He is an ordinary human who shares similar sentiment as other athletes. He considered doing 4Lo before WC when he couldn't do the 4t due to his injury, but decided against it eventually because he wanted to win too much and didn't want to take the risk. He considered retiring and taking a season off after Sochi just like many Olympic champs did after winning the Olympics. The main reason he still has the motivation to continue competing after the Olympics and is still willing to take the risk to upgrade his layout after winning all major titles and breaking WR is because he didn't win the Olympics with a good performance, barely won the 2014 WC, lost to Chan and Fernandez and lost worlds two years in a row.