Its hard to say statements like that universally because it really depends on where you work (and have worked). There are plenty of places which make time to refactor along the way, in small and large ways. Its good engineering, and a healthy code base nets better long term outcomes for the business too. Business people care about the team's velocity (since programmers are expensive). And I'm disheartened you think its the norm but not all companies have MBAs telling software engineers how to do our jobs. (Eg, Google / Facebook / Netflix / Github / etc.)
> Do you have any evidence to back up your claim or is this just your opinion?
Its just my professional opinion, backed up by almost 30 years writing software at all sorts of companies and in all sorts of environments. But no, I wish we had quantitative evidence for this stuff. But there's a weird dearth of quantitative research around software engineering. We as an industry don't really know what we're doing yet. I'd love to read some studies on this stuff if you can find any.
But I'm very confident about what works best for me, from trying lots of things on solo projects. I'm way more productive when I throw something together quickly, iterate like mad on how it works internally, then tidy it up and modularize as I get more confident around the best way to structure the code. Whenever I modularize up front I basically always end up regretting my abstraction boundaries - and either have to rework them (which is expensive) or I leave them alone, and just ship vaguely mediocre code.
But if prematurely modularizing your code is the only way you can modularize anything at your workplace then - well, you do you. But I find that pretty sad.
