Actually, it's the exact opposite. The security of a blockchain is fundamentally dependent on mining being expensive. That is the only defense against a 51% attack. Cheap energy just drives up consumption to the point where mining is expensive enough to deter attacks.

This is ultimately what I think will sink blockchain as a medium of exchange (not necessarily as a store of value). By its very nature it cannot be cheap, so TTPs will always be able to beat it on price.

I'm not even sure that mining being expensive is a great defense against a 51% attack.

If things do end up being an oligopoly, then any one of the members of that oligopoly will only have a relatively small sprint between their current position and a 51% attack. And quite a few options for how to attempt such a sprint.

I meant that the variation in electricity costs harms the reputation of the blockchain. Work needs to be approximately the same difficulty for everyone.

  Work needs to be approximately the same difficulty for everyone

Unfortunately the main design and math of of Satoshi's PoW means that users who ran the BTC software app 2009-2014 worked far far far less and spent much less CAPEX and OPEX to generate the majority of BTC that will ever exist.

Sorry, more clarification -- same difficulty at roughly the same time, not same difficulty across time.

Edit: It seems this thread has gone off on a tangent. I was adding to the discussion of flawed assumptions, not ethics.

Why not the same difficulty across time to give all users equal fair access?

Perhaps it would diminish the ability for early users to extract wealth and capital from later users?