It is not some big conspiracy.
Wired headphones have many pros, but also many cons. Wireless headphones have many pros, but also many cons. You can still buy wired headphones for modern phones using USB-C.
The vast majority of people literally don’t care or prefer having wireless air buds. The people who don’t, still can have wired ones.
The major distinction is that the headphone jack is large and not easily waterproofed. The trade off of having a sealed water tight phone at the cost of losing the headphone jack is worth it for the vast majority of people. It is worth it to me.
If you don’t like it, go buy a Zune.