I think it takes time for these things to settle in. Gerrit Cole wasn't looking like a HOF level pitcher until he was 27 or 28. It seems like you have to be good until your mid to late 30's to be a HOF pitcher... Verlander, Scherzer, Kershaw, etc.
Burnes could be a candidate if his arm doesn't break and he sustains his peak for a few more years.