I agree with others, I think you are way underestimating how much Kilian is making. According to a quick google Salomons parent company makes a combined estimate of 1.7 billion. How many other athletes representing these companies can people even name or recognize? I am sure most of us know of many of the other well known ones but Kilian is ridiculously famous internationally. I mean, the guy moved to Norway partly because he was constantly being stopped for pictures while out training. But what other athletes are so synonymous with their main sponsor the way Kilian is with Salomon? I imagine if he were to drop Salomon for some other company would be a massive blow to them, they've got to be paying him a huge amount of money. Working in the corporate world for nearly 20 years, I know that just regular sales guys from smaller companies that make well over 200k a year and I have an extremely hard time believing Kilian makes less than an average sales guy.
I also think you are overestimating how much Olympians make, plenty of articles out there about how little they actually make. Yeah theres a bonus for the medal, and then some sponsorships. But most of these folks have to have a regular job of some kind.
Add in the fact that pretty much his whole life is paid for in terms of, equipment and travel, I imagine he doesn't pay a cent for most of his personal belongings. He and Emelie likely own their property outright. So that just leaves food and whatever other expenses are not covered by his many sponsors.