There is a distinction between necessary complexity and "busy beaver" artificial complexity. And it turns out that there's a pretty compelling mapping between energy and information and fundamental complexity. There's a reason they both use a concept of 'entropy'.
That said, there's no denying that there's probably a lot of unnecessary complexity in most software.
I'm sorry without some citations this is still handwavy bollocks.
Energy does have a conservation law. Entropy does not. Not does information, complexity etc.
I majored in phyiscs, I'm familiar with these terms.
Grand parent post made no indication they were talking about essential complexity when they made their bold assertion about how it's conserved like energy.
I'm also not aware of any formal or precise way of measuring "essential complexity". Not in the way we do for energy or entropy.
That said, there's no denying that there's probably a lot of unnecessary complexity in most software.