I just realized there is also even a pretty simple but compelling quantitative argument that mining technology cannot have changed much, if anything at all. Consider this.

1. Since 2011 the hash efficiency has increased by a factor of more than 1000 (compare table 2 here)
2. Since Bitcoin mining has become commercialised, the electricity costs are always less than the mining reward, since that's what pays for the mining.
3. Today the electricity costs are at least 50% of the mining reward (see calculation below).

So: if better hashing efficiency by miners would help - where did that thousandfold increase in hashing energy efficiency go?

(That is, of course, a rhetorical question - it went into the automatic difficulty adjustment that by design makes sure no improvement in mining technology can ever bring the resource usage of bitcoin mining seriously down. If you read that article I cited you realize this is intentional.)

Here is the calculation for point 3:

The Cambridge Bitcoin Electricity Consumption Index estimates the Bitcoin energy usage to an absolute minimum of 9.5GW, and the average electricity price to 0.05 USD/kWh. The bitcoin reward is 6.25 BTC per 10 minutes, that is 37.5 BTC/h = 937500 US-$ per hour. The electricity spent on bitcoin would cost 9.5GW * 0.05 USD/kWh = 475000 US-$, that is about 50% of the mining reward.

(The lower bound the CBECI 9.5GW one year is 83.22 TWh per year, which is about 0.28% of the world electricity production of about 30000TWh - their actual estimation is 15GW. That seems reliable enough since it is in the same ballpark as with other estimations in the last few years: 0,16% and 0,55% .)

I just realized there is also even a pretty simple but compelling quantitative argument that mining technology cannot have changed much, if anything at all. Consider this.

1. Since 2011 the hash efficiency has increased by a factor of more than 1000 (compare table 2 here)
2. Since Bitcoin mining has become commercialised, the electricity costs are always less than the mining reward, since that's what pays for the mining.
3. Today the electricity costs are at least 50% of the mining reward (see calculation below).

So: if better hashing efficiency by miners would help - where did that thousandfold increase in hashing energy efficiency go?

(That is, of course, a rhetorical question - it went into the automatic difficulty adjustment that by design makes sure no improvement in mining technology can ever bring the resource usage of bitcoin mining seriously down. If you read that article I cited you realize this is intentional.)

Here is the calculation for point 3:

The Cambridge Bitcoin Electricity Consumption Index estimates the Bitcoin energy usage to an absolute minimum of 9.5GW, and the average electricity price to 0.05 USD/kWh. The bitcoin reward is 6.25 BTC per 10 minutes, that is 37.5 BTC/h = 937500 US-$ per hour. The electricity spent on bitcoin would cost 9.5GW * 0.05 USD/kWh = 475000 US-$, that is about 50% of the mining reward.

(The lower bound the CBECI 9.5GW one year is 83.22 TWh per year, which is about 0.28% of the world electricity production of about 30000TWh a year - their actual estimation is 15GW. That seems reliable enough since it is in the same ballpark as with other estimations in the last few years: 0,16% and 0,55% .)