Software development is a very young and immature field compared to many fields/industries.
I mean, the Hippocratic Oath and _some_ form of organised medicine has been around for 2,500+ years.
Modern manufacturing has been around for a few centuries.
etc.
Yes, they all change and develop - and use software within them to drive some of that change - but many industries are mature and stable.
Software is not.
5 years ago you would build a frontend website one way, now you'd use a completely different set of tools/technologies. Wait 5 years and it will have completely changed again.
It's a similar case with software development methodologies, backend approaches/languages (etc), too.
Plus many industries have some form of enforced standards or monitoring, whilst software certainly does not.