A transaction incurs one-time electricity costs for the miner, but also permanent storage costs for miners (who must have a full blockchain copy). For a miner,

A transaction incurs one-time electricity costs for the miner, but also permanent storage costs for miners (who must have a full blockchain copy). For a miner, currently the latter is negligible. Increasing block size implies more storage space needed, which would push amateur miners out, making Bitcoin less decentralized than now[0]. Over time, the storage costs will become massive. This is why block sizes have stayed relatively low. One reason I'm bearish on Bitcoin is that it's absurd that a one-time fee allows you to essentially have a permanent public billboard. For example, people have posted links to illegal content on the blockchain that is essentially unremovable[1]. [0]: https://eprint.iacr.org/2013/829.pdf https://eprint.iacr.org/2013/829.pdf [1]: https://www.bbc.com/news/technology-47130268 https://www.bbc.com/news/technology-47130268