What is Jakob's current threshold speed?

Well as Bakken proved that depends on the length of the interval. But if I have to imagine he only runs slightly faster than he did in 2019 when his training was published. Probably 62-63 for the 400s, close to 2:40 for the 1000s, and 2:50-2:55 for the 6-minute reps.

He might be able to run around 4:25 pace for an hour, if you are going by the standard definition of "pace you can hold for around an hour"

i'd wager that he works out faster than that though

Threshold speed is too unspecific to use in this context. Too many different definitions. Anaerobic threshold is just a simplified theoretical model of exercise physiology. But sure, he's up there, among the best ever. Probably 58-59 min in a half marathon.

People who ask questions like this are the absolute worst people alive.

Do you have a link to his published training?

We have incels, racists, and other kinds of undesirables on this board, and this question is what triggers you?