Microsoft have a goal that states they want to get to " 1 engineer, 1 month, 1 million lines of code. " You can't do that if you write the code yourself. That means they'll always be chasing the best model. Right now, that's Opus 4.5.
Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.
I miss those days.