I was a professional games developer for 15 years, ran my own studio of 28 developers, worked for a number more and have released several games on Steam and other platforms so I am confident when I say optimisation is something you try to do as you go along a bit, but honestly most of it has to take place towards the end when you remove debug code and prepare the code base for release and do a general performance overview. It is just not practical to dedicate too much time to optimisation during primary development as you are often rewriting entire chunks of code so optimising them would be a waste of everyone's time and effort. Besides you have to optimise towards a specific goal and platform and again that requires the game to be essentially feature complete to do so. You might not like it, and that's fine, but there are good reason a team doesn't spend to much time optimising. Development takes a keen eye, patience and time. I hope that helps.