You're missing a few pieces. The amount of electricity needed to protect the network is directly tied to the value of the block reward. This depends on the val

You're missing a few pieces. The amount of electricity needed to protect the network is directly tied to the value of the block reward. This depends on the value of bitcoin, true, but also the amount users are paying in fees and the reward era we are in (see https://en.bitcoin.it/wiki/Controlled_supply https://en.bitcoin.it/wiki/Controlled_supply).