Software projects (like most things) are typically held to a deadline. In my experience, this is usually just to keep teams of developers accountable to business outcomes. Most of the time, the developers don't get any substantial rewards for being on time, and no one gets fired if the project is a little late. If anything, blame goes to the project managers who promised the deadlines.
The point of a deadline is to ensure the development team doesn't waste time. You don't want perfectionism delaying the project indefinitely. It's better to release something imperfect so you can get customer feedback and iterate.
Deadlines are bad when this is their only purpose. Developers know when they're being forced to work long hours for no good reason. Good developers understand the business goals and want to contribute to that goal. The best developers know how to avoid wasting time and can help others on the team do the same.
It's better to align developer incentives with business outcomes than to impose meaningless deadlines.
A bad deadline can mean releasing a broken product. In a centralized environment, you can always fix it later because you have complete control. Blockchains are decentralized as soon as they're released. It's significantly more work to coordinate a fix after release than to just put in the extra time to get it right before releasing.
The Koinos Group originally estimated Koinos mainnet for Q4 2021, but that was always an estimate--not a deadline. The team isn't getting paid by anyone. They're all founders with equity and token holders. Their incentives are 100% aligned.
P.S. A lot of people ask about Koinos "project delays" and "broken promises" like they're entitled and impatient. Good things come to those who wait.