Bullshit. Good software is never mature, it evolves over time. A good software architect, or ideally any dev should be a good software architect, will make sure it stays on course to: little tech debt and doesn't become toxic.
Just because you've been working on shit show projects that doesn't mean all projects are mismanaged like that.
Billions of in-house apps, for companies > ten years old.
The link above details several more, read it.
P.S. Gnaritas, you're dead. Tried vouching, didn't work.
Plenty of companies aren't attracted to the new shiny.
So you've never worked in good code, that's all. Most of the world runs on software evolved over greater than 10 years. Everything you said is wrong, because you've been surfing trendy crap that businesses mostly ignore. Good architects don't use immature languages that might not be around in 10 years, they're smarter than that.