Next to nonexistent cost per connection in standard case of SSL. We can saturate gigabit links using modern hardware with AES-NI. Outside of special deployment cases, the cost is a rounding error. We can't provide this capability in a cheaper way at the moment (or we would do that)
On the other hand, we've got Bitcoin which chugs energy/money by design, while other solutions like proof of stake / space / ... exist and are much more energy efficient. People concisely decide to burn money to keep this system running - that's why it's unreasonable.
They are only proposed solutions, not implemented in any existing systems so it's not fair to compare them. Proof of stake for example has numerous drawbacks: https://en.wikipedia.org/wiki/Proof-of-stake#Criticism
And protecting money is not important?
> - RFC: we're wasting a few bits as a tradeoff for less complicated hardware and less processing power. Not sure if applicable anymore, but reserved fields and consistent parsing saved us some power/materials historically.
Well so the RFC reserved bits are waste but also a benefit? Maybe the same is true w.r.t Bitcoin mining?
> - SSL provides security and privacy in your communication at a cost reasonable for the outcome.
The cost is reasonable in SSL case but unreasonable in Bitcoin case based on what criteria exactly? Remember that SSL relies on PKI that has a lot weaker security guarantees (see Symantec, DigiNotar and your favourite Chinese CA in your OS's trust store).