Why would it take a single engineer 3+ years to build a Mario-like game with a tweak around time-mechanics? I am discounting the artwork and asking primarily a

Why would it take a single engineer 3+ years to build a Mario-like game with a tweak around time-mechanics? I am discounting the artwork and asking primarily around the efficiency of the coding and development. Each developer has a focus area. You might focus on millisecond level optimization; a web-developer might focus on content provisioning and rapid development; a data engineer might care more about sanity and robustness of data. It's not clear how anyone can judge other engineers' ability based on arbitrary metrics without considering their engineering system's goals and requirements. As an example, both Braid and The Witness have very limited accessibility; perhaps that wasn't a focus area of yours and again each developer to his/her own.