The current high schoolers have been training with lesser talents and they have not been trained from age 12 or younger by a professional coach with two other European medalists in the stable; nor have they been running professional meets and a professional runner for years already.
That is why you see very large improvements by many college freshmen and sophomores. Jakob leveled off last year with a 1 second improvement in the 1500m. He showed nothing new at 800m, where a breakthrough should really precede a 3:28 in the 1500m. I would not have been surprised to see him run 3:29 this year at all, or 12:50s, because he was already at that level last year with the Lausanne race where he would have been sub 3:30 had he not jogged it in the last few steps and given his close against Gebrihwet, he had sub 13 in him that day easily. But he didn't show dramatic improvement. I'd like to see him run 1:43-44 before I predict him running 3:28. He could still do it but speed is a bit of a limiting factor. We'll see. Last year he was not on Tim's level.