I think LCW has to change his game from counter attacking, fast footwork and powerful smashes to more strategy focus style of play like LD, if he wants to keep going.
LCW is trying to change his style. In the WC, he played defensive and at a slower pace because he wanted to conserve his stamina and energy until the later rounds, especially against LD and Chen Long. But LCW ended up in 3 sets and got knocked out by Bryce.
LCW has always relied on his speed and smashes to overcome his opponent. Yes, LCW is skilled, but he is not as skilled as LD. That's one of the differences between him and LD. The other difference is, LD switched to a defensive style back in 2013 when he won the WC. LD suddenly became a very defensive, rally styled player at the 2013 WC and he won with it. So LD has been practicing the defensive, rally style, for 4 years.
LCW just started switching to a defensive, slow paced style this year. It's great if LCW can win in 2 sets. If the match goes to 3 sets though, LCW's stamina is at a large disadvantage because of his age. If you watch the 3rd set against Prannoy, it's clear that Prannoy is the faster player and Prannoy has more stamina and energy compared to LCW. In the past, LCW was rarely the slower player in the 3rd set.
LD is one year younger than LCW and LD is also more skilled. This will allow LD to play at the top level a little longer. But even age is working against LD these days. The last time LD was truly the best player in the world was 2014 when he beat Chen Long at the Asia Game finals (LD did not play at the WC that year). I don't think LD has been the best player since then and his game has been dropping too, although LD is better than LCW at this moment of time.