Why most software takes quarters
The reason software usually takes quarters is rarely the coding — it is the hand-offs. A strategist writes a brief, a designer interprets it, a project manager translates it into tickets, and an offshore team builds an approximation of an approximation. Every hand-off loses information and adds a delay.
Each layer also has an incentive to protect itself rather than ship, so timelines stretch and the thing that finally arrives is a diluted version of the original idea. Remove the layers and most of the delay disappears with them.