Calculating Duration based on Effort and Resource Allocation %

Why has product development ignored the need of real project managers to be able to calculate durations based on task effort and resource allocation percentages?

This is one of the most basic needs of a project management tool and SS's response that 70% of PMs say this functionality is not needed is fatuous at best. These "less formal" project managers are not project managers.

Currently I need to build my schedules in the program my organization retired in order to begin using SS and then move that info into SS once my schedule is baked so that I am not spending countless hours doing those calculations myself, especially for my lengthy projects that can last multiple years.

Unfortunately, I am not in a position to decide to cancel my organization's subscription, but implementing SS has made my job exponentially more difficult.

PMs have been begging for this for at least the last 5 years and so far SS has completely ignored this request. Frankly, it's insulting.