It's more than the fear of over-engineering.

For example, with startups the time to market, pivots, and not owning your decisions long term (which often happens) leads people to move fast and not consider consequences.

It's about goals and following the money. If a bridge fails there's significant legal liability, guilt over lost lives, and more. If software doesn't scale is can be rewritten or a company is hacked and customer info gets out there is a marketing black eye. It's different.

I say this as a classically trained engineer who thinks more engineering needs to be layered into software development. We need to justify it to the business.