The counter party risk is not with the miners. If it is I must be misunderstanding what you mean by this. Bitcoin doesn't prevent counter party risk but it is the first asset where the amount has no bearing on difficulty of custody. One huge problem with gold is that it is difficult to secure large amounts of it. Bitcoin doesn't have this issue.

Not sure this is what you mean but let's say 50% of miners drop out. Or maybe more, pick a number. The difficulty adjustment would adjust and mining would continue. This happened when China banned bitcoin mining. We already know how that works.

I would say the bigger issue would be why would so many miners stop mining? If the reason was economic then we have an issue. If it is a nation state action then other nations would likely jump on the opportunity.