Thanks to someone in the Cooperative Development chatroom I just learned about a new co-op model I've never heard of before: a cooperative work pool!
TL;DR a bike shop and a ski shop could setup a work pool. In the winter when the bike shop doesn't have enough customers, the employees go work for the ski shop where it's the busy season (and during the summer they go back to the bike shop). This would be much better than getting fired every winter!
@pkw yah, I've been at bike shops that did ski stuff specifically to try and pad out the winter months and not have to fire people or reduce hours, but it wasn't their specialty so they ended up not doing it as well as a proper ski shop. Forming a b2b co-op and agreeing to trade off employees seems like a much better way to do things and keep everybody employed!