Why is playing on a B team admitting defeat? Did your older son admit defeat? A real shame you think this way. And maybe you should consider that your view is holding your son back.
You say your son was under utilized. That's code for not playing, right? Maybe he'd play more on a B team. That's not admitting defeat but it could be having fun. I'm sure you think he was an A player. But after being underutilized and being cut maybe not. What's the value in the label of A anyway?