I've seen Michael Saylor make the argument that bitcoin's network security increases with the hashrate, but if it costs the same amount of energy / capital to produce that hashrate, does the network security really increase?

I'm generally more of the opinion that the true security of the Bitcoin network comes from the fact that it costs way too much for an attacker to try to 51% attack it since they would have to spend more capital and energy than the rest of the entire network to achieve it.

What are your thoughts? Does bitcoins decentralization and security come from distributed energy use towards achieving that hashrate, or just simply hashrate? I also might be completely mischaracterizing his argument, so forgive me if I am.