He's so underappreciated that even his appreciation thread spells his name wrong.
He only took up cycling at 16, then during his U23 years, he was trying to combine cycling with studying to become a PE teacher and he says the physical demands of doing both at the same time were too much. He eventually gave up on the latter to try and pursue a cycling career through the Dutch continental scene. Then, when he finally managed to escape that at 25 off the back of his first fullpro win at Druivenkoers, it was first for Riwal and then for Rally/HPH, teams where nobody really performed well (and even then he did fairly well at the latter). So basically all the ingredients for a late bloomer career were there before he went to Tudor, the first good team he's been at, the first team that's given him a proper train to work with, and it's showing. That said, these heights have to be a surprise for everyone...