There are bad players who know openings, but there an no good players who don’t know openings. Without opening theory you will just get worse middle game again

There are bad players who know openings, but there an no good players who don’t know openings. Without opening theory you will just get worse middle game against any competent opponent. Furthermore, if you could just calculate everything ab inito your play would be identical to “memorized opening,” alpha zero did learn a lot of standard openings from self-play (without being shown these opening explicitly). If someone plays a “bad” opening in a serious game it’s because not only they don’t know theory but they also can’t calculate well enough.