My impression is that it's simply harder to get promoted as an engineer in the industry by using boring, sustainable, unexciting solutions that have been used by everybody else and their dog. How do you even stand out that way? Looks bad on the resume, like you didn't even try. Great for the business, but maybe terrible for one's career?

You could turn that one Rails app into a complex microservices architecture and do a conference talk about it, and get a promotion. Then you can undo the microservices architecture, write a blog post about returning to the majestic monolith, and do another conference talk about it, maybe get another promotion. Abstract, de-abstract, bundle, unbundle, rinse and repeat.

It feels like a tragic situation that's nobody's fault, just the reality of human psychology being wired to reward the wrong things.