Scrum/Agile is basically an answer for things that went wrong in the past. Building software has a long history of delays, running over time, running out of budgets, etc. As a stakeholder/customer, you need certainties up front: how long is it going to take, what is it going to cost? And if you think this isn't reasonable, just consider, would you hire a contractor to work on your house that can't tell you up front cost and duration?
Anybody doing work needs to be able to estimate duration, progress, risk of delays, etc. Other people's work depends on your deadlines. Go/no go of a project depends on cost and duration.
Insight and tracking is required. None of this was done any better before agile.
What is required is frank conversation with the stakeholder/customer, because there are so many trade offs decision to make. Devs don’t like to estimate tasks because there’s an exploration phase (which cost time an energy) to have the solution and the cost of time and energy for the implementation. And it’s recursive. Agile was basically saying, let the devs do their thing, but have a conversation every once in a while to discuss new directions to the projects based on new evidence found. And unless the team have already built the same project (with the same people involved), it will always be a bet. No amount of tracking or insight will remedy that.
Agile recognizes that software development is a design process with uncertainties and not a repeated tested manufacturing process (product development versus product manufacturing). With the uncertainty of a design process in mind, and the need for estimates, it suggests comparing similar tasks to get an empirical estimate. But since it's just an estimate, you regularly need to validate that the estimate is still considered correct.
Anybody doing work needs to be able to estimate duration, progress, risk of delays, etc. Other people's work depends on your deadlines. Go/no go of a project depends on cost and duration.
Insight and tracking is required. None of this was done any better before agile.