We are always balancing a set of constraints: total cost, speed of delivery, certainty of cost, and certainty of delivery for a given date are but four.
The real problem is that management think they can directly constrain those kinds of variables but in reality they are not inputs they're outputs. The real inputs are things you can actually control like what you're building and which of your team you assign to build which parts of it at which times. That might come in on time and under budget or it might not but shortening a timeline or decreasing a budget won't change how long it takes or what it costs.
Of course that sucks for managers who want to make informed decisions like whether to go ahead with a project that will require an uncertain amount of investment to complete but needs to generate more return than some threshold to be worth doing. Now the managers have to find a way to guess what the important outputs like cost and timescales will be as some sort of probability curve so they can make a rational decision based on the best but still incomplete information they have available. And even then a lot of managers insist on trying to be absolute about things like time and money when the actionable decisions they need to make are more often whether to start some project at all or which ongoing projects currently have the greatest need for any additional resources that are available.
The real problem is that management think they can directly constrain those kinds of variables but in reality they are not inputs they're outputs. The real inputs are things you can actually control like what you're building and which of your team you assign to build which parts of it at which times. That might come in on time and under budget or it might not but shortening a timeline or decreasing a budget won't change how long it takes or what it costs.
Of course that sucks for managers who want to make informed decisions like whether to go ahead with a project that will require an uncertain amount of investment to complete but needs to generate more return than some threshold to be worth doing. Now the managers have to find a way to guess what the important outputs like cost and timescales will be as some sort of probability curve so they can make a rational decision based on the best but still incomplete information they have available. And even then a lot of managers insist on trying to be absolute about things like time and money when the actionable decisions they need to make are more often whether to start some project at all or which ongoing projects currently have the greatest need for any additional resources that are available.