I am doing a deep dive into the psychology behind PoW algorithms. You make a very interesting assumption here, but I would really like to analyze this more in depth, because I think it is more complex than what you have implicitly assumed.

Can you expand on exactly "why" risk of loss is important during block generation? What do you think the result would be if PoW was not a competition, and instead everyone was guaranteed to be allocated a reward for doing work, rather than only a statistically probable percentage of a larger reward, which effectively acts as a proxy for the same thing?  Seems to me those would be mathematically equal in the limit, and I am trying to understand the underlying psychology for this belief?

You are not the only one who has it obviously, so I really want to figure out if there is merit to it which I do not yet understand, or if it is simply a value choice because that is how it has always been done?

Re: your second sentence. The difference between PoC and PoS, is that capacity requires you to expend resources outside of the system you are securing. With PoS, nothing in the world could make an oligarchy give up control if they did not want to.  Thus, 51% of a PoC system would always be a temporary condition in the presence of a determined outside force, where as 51% of PoS would be permanent and entirely subject to the whims of those who control it.

I don't see where "risk of loss" really enters into the equation.

Would anyone care to expand on this and help me out?