"No, it's less effort than that"

Whenever this estimation question comes up, developers rarely put themselves in the shoes of the business side, and try to understand why there needs to be an estimate, and why shorter is always better than longer. What they do instead, is try to protect their holy land of software development, and exacerbate the differences between engineers and "the others" - sarcasm and cynisism usually shine through at this time, and that's how you end up with unrealistic estimations.

I've been a developer, PO, manager, director, CTO, the whole thing. I'm still shocked by how most (not all, but most) developers are simply too disconnected from the reality that, yes, they do need to provide value, and yes, that value does have a time factor. Lucky are we as developers, that people actually ASK us how long it will take, and give us the opportunity to explain it, push back, and actually defend your estimates. The sad reality (at least from 90% of my career), is that developers are rarely able to actually engage in business-level conversations, and actually express their thoughts/ideas/concerns/proposals, in a way that it drives the conversation forward. In a way that helps PMs and managers actually see the complexities of the work, and engage in healthy cost/benefit discussions.

Well then bussiness people are also disconnected from reality. If a developer can write code and estimate and deliver in time for bussiness, then he is not an employee. He is a founder. What you want is people that deliver like a founder but that don't get any share of the profits. You want gullible people.