In what races?As for Valgren - yes he can do the same job - but both Honore and Kron have been better, last year and this year
Kron has never ridden a Monument in his life. As far as I know, the longest race he's done was the NC last week, and it's not like he won with a one minute gap on the peloton.
Honore has ridden 2 Monuments in his life and cracked the top50 once (yes, he was working for others, but still...).
In the time frame you mention Valgren was 11th in a very hard WC, 21th in the Ronde, 13th in AGR. He also has a history of overperforming in national teams events, as @Samu Cuenca says.
The youngsters have surely impressed in the last few months, but this is a different beast entirely. We're talking about 237 km Olympic course with almost 5000 mt of climbing. Winning a Catalunya or Itzulia stage to me has little relevance in this context.