"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.

Everyone understands that why the business needs to an estimate and that shorter is better than longer. There is no ambiguity there at all. The complaint is the phrasing like the developer can know when it'll be finished. Someone's ability to deliver value quickly is unrelated to their ability to estimate how long it will take. They can get their estimate completely wrong and deliver huge value. And we all know if there was some way of estimating how long software tasks would take, software companies would hire a professional estimators for the same reason that software companies often develop product teams to negotiate what features a product should support. There is no point asking devs to do it. Oh course, no-one else can either and the devs will at least get the lower bound right so people bother them but the process is transparently stupid.

To know how long something will take it is necessary to list all the steps taken to do the thing. That just isn't possible in software development. Developers can come up with a lower bound for a given set of requirements. And I think everyone agrees that they could do an accurate estimate assuming nothing unexpected happens. Then, in 95-98% of projects, the estimate turns out to be under-calling how long a project will take. The "developer estimates" becomes a measure of how much fat the developer feels like putting in the system this project.

Asking for estimates completely misframes the conversation. The question is what problems does the business have now, what problems are likely to develop in 6 months, and some input from the developer on the cost-benefit of trying to solve those problems. Then people make some qualitative decisions with an eye on minimising risk. The best outcome after giving software estimates is that everyone ignores and forgets them - anything else destroys business value.