I have this same issue.Ditto. Good to hear. In my case, though, it only works with supportive insoles.
With ski boots, if I stand in the shells sans liner, on a stock footbed, my ankles hit the shells on one side and there is a huge gap on the other.
In running shoes, I can run OK with a neutral shoe, but I feel better on longer runs in a more supportive shoe for pronators. Interestingly, I feel good running in those minimalist FiveFingers which mimic barefoot running.
The flexibility of a running shoe compared to a ski boot probably allows my foot to adjust as its flexed and the FiveFingers allows my toes to spread which supports my foot.
In a skate ski boot (more rigid that a running shoe but not quite as stiff-soled as an alpine boot) I also need some arch support or my foot roles towards the inside on the glide.
I do wonder if those with super strong feet (rock climbers, dancers, gymnasts, etc) can do without supportive insoles in athletic footwear.