4-3 Cover 2 doesn't always translate well against the spread teams we have nowadays....too many holes.
Base Cover 2 leaves two WR uncovered in a traditional 4 wide set (1 WR in a 3 wide set). With the safety so far off the ball, it leaves bubble screens wide open for easy 5 yards, or much more. It also opens up the field if you run smash routes with 3 deep routes. It stretches the safeties hoizontally with 3 WR on 2 deep S, but also stretches the CB vertically if they run with the deep WR, opening up a huge gap for a simple curl or out. If you run cover 2, you need to rotate into a robber coverage at the snap with single high S in the middle and another safety over the slot with outside technique and inside help with the LB.
In base 4-3, cover 3 and cover 4 usually work a little better againt spread. You can run cover 2, but you need to disguise and rotate based on WR sets.