Going 4 wide is not common on "proper" ovals, meaning those best suited for open wheel competition. At Indy, 3 wide is like
. Most often cars are single file with a racing line and a passing line. I can see almost all of turn 1 in my seats, and see 3 wide racing a few times a race. The speeds they take the turns at are also lower. This, combined with a longer track means everyone effectively has more room and is more certain about what other drivers are doing - unlike LV, where you can be wheel to wheel for laps at a time averaging over 220mph, especially with that many cars on the track. When the 33 get spread out at Indy it's basically a constant stream of cars going by. Now look at how bunched up the same amount of cars on a track a mile shorter.
These tracks work in NASCAR because of one simple thing - the bodywork. Bumping in NASCAR does not necessarily cause major accidents like touching wheels does in open wheel cars. But open wheelers have been racing on ovals since racing's inception and have been doing so relatively safely. As unfortunate as it is, moving away from ovals entirely is an overreaction. There is a huge difference from a flatter squared off type oval track, and a high banked bowl type oval.
FWIW I've climbed the 9* banks at Indy. In person and close up, they seem ridiculously steep. I can't imagine a 20* banking