Its probably a mixture of pushing the bike and freshness. An world class effort like Kienle and Frodo did this summer probably takes its toll. Especially when you have some ironman seasons before. Often it seems like less ( Ironman) is more , especially with age. Both left with not enough power for winning. Kienle looked weaker than normal and still finished 4th..
Its nice to see the bike effecting the race a bit more this year. (Beeing off in front)

Nilsson had a awesome rookie race. With more race experience in Kona he will do even better. Maybe a bigger bike engine would save him even more for his run, even if it was good enough to be close to Lange he seemed to be more effected than Lange .