importantly, that magic is from schnorr signatures. no other feature of taproot enables it. a schnorr monetarty only tx could enable this too. also same principle for stealth lightning channel open/close txs. schnorr enables aggregation of both pubkeys and signatures from the same corresponding set of keys. this property is related to the simpler algorithm. the signature was patented until february 20, 2010 (us patent 4,995,082, filed feb 20, 1990). this is why it was not in bitcoin from genesis.