The reason less experienced players get obsessed with openings is because they make regular tactical mistakes in the opening, and then blame lack of opening knowledge, as opposed to their lack of tactical ability. In other words they try to memorize their way out of tactical mistakes, which is impossible. At that point, after it inevitably fails to work, they claim they've plateaued, lack the IQ, maybe the memory, maybe are too old, or whatever other excuse.
This is made even worse by the fact that opening knowledge is ostensibly easy to improve whereas tactical vision seems very difficult to improve. In reality it's the exact opposite. Exact opening lines will fade from your mind rapidly (though general ideas will stay with you forever - but that's another topic), whereas grinding tactics might not 'feel' like you've learned anything, but overtime will permanently train your intuition to where it needs to be to start seeing major gains.
On top of all of this - one could simply play 'freestyle' chess (the starting pieces locations are randomized) and suddenly there is 0 opening theory. But you'll find that your freestyle rating is going to be strongly proportional to your 'normal' chess rating!