Why is everything that the government does so expensive?

I have for years wondered about one of the biggest mysteries of life: Why is everything that the government does so expensive?

And to be more precise: Why is everything that the government does that's something that private citizens/companies also do, always so astonishing expensive?

As a private citizen, go to a sculptor, for example, and commission a hand-made human-sized statue or wooden carving. Depending on the quality and status of the artist, it may cost you anywhere from some thousands of dollars/euros to maybe a few tens of thousands, at the very most, if it's a really professional high-quality work.

However, when the government commission that exact same thing, it will invariably cost at a minimum ten times more. In the hundreds of thousands dollars/euros. Heck, even millions being spent on such a sculpture doesn't even bat people's eye.

As a private citizen, hire a company to fully renovate and modernize your home? Again, you might have to spend some tens of thousands of dollars/euros.

The government doing the exact same thing, for the exact same type of house? Hundreds of thousands, if not even millions.

Create a 1-minute advertisement or PSA in the form of a video that has perhaps a bit of acting, a bit of computer-generated graphical design and some narration voiceover? People on websites life Fiverr will do that for you for a few hundred bucks, maybe a few thousand. Even some professional studio will likely do that for some thousand bucks, maybe a couple tens of thousands at most.

Again, if the government is commissioning such a thing, multiply that by ten. Or by a hundred, easily.

And mind you, in many, perhaps even most countries the government is required by law to always commission works as cheaply as possible.

This is so ubiquitous that nobody even bats an eye. Everybody just expects it, because it always happens. But why? I have never heard any explanation for this.