This "software grows too complex" is certainly a culture issue, and not a software problem. It mostly comes from businesses throwing a bunch of under-skilled labor at the problem, and demanding more and more too quickly. Of course it will outgrow the ability of that team to work with, reason about, keep clean, and extend. They will get frustrated and move on, and a new group comes in, re-writes it from scratch, and so it goes.

Look at software that has been around for decades, continues to improve, never "needs" a re-write, and will never be re-written. It exists and is not uncommon. Things like the linux kernel, all the GNU utils, emacs, vim, apache, nginx, postgres. The list goes on. We know how to write software that lasts for decades, continuously improves, and doesn't need constant re-writes. You give it to skilled people who care about it, and don't put artificial corporate constraints or impose fad architectures on them.

I'm not saying the corporate model is "wrong" - it works. "Works" means it builds companies and generates profit. That is the goal. But it will not generate stable long lived well designed software. That's okay though because that isn't the goal. Sure, the poor quality cuts into the margins a bit, but not enough to matter.