ACM did not go out the window. People thought ACM went out of window, but the geometry of a missile shot dictates moving to a position to gain a high PK firing solution, or you miss.
Missiles are not death-sticks. Use it right, or miss horribly. The technology helps, but it doesn't change the fact you still have to put yourself in the proper position to make reliable kill shots.
and stealth != invisibility. It simply cuts your detection range drastically. F-35 and F-22 have that massive advantage over everything else, and it really is massive. You up an entire wing of Su-30MKK, and you're still pretty boned. AWACS sees you, makes a radio call, and fighters you can't see coming are now between you and your base. If you don't keep running straight from them, you eat missiles.