Why Is It More Important Today Than Decades Ago to Evaluate

Why is it more important today than decades ago to evaluate the performance of software?

A) Hardware is so fast that the real limiting factor in a computer is the software.
B) Hardware is becoming increasingly similar, even between systems constructed by different vendors, so the software affects performance the most.
C) Software is becoming increasingly complex so it is harder for programmers to determine if their code is efficient by just looking at the code.
D) Software is becoming increasingly complex and often hides the hardware from the user, creating a virtual machine. Cumbersome software can cause a system to execute slowly, even with the most powerful hardware.