There's some competition, yes, but it's bounded — even the most extravagant Christmas display is nowhere near the maximum amount of lights which could be placed in the space, not to mention only operating for a few weeks a year.

The design of Bitcoin ensures that does _not_ happen there, and it's currently using a massive amount of power to process a tiny fraction of the total economy, especially after you account for the transactions which are not linked to real economic value (money laundering, wash trading, etc.). The design ensures that if someone did find a useful application which saw popular adoption, usage would need to be many orders of magnitude higher than it is now.