Hey, I never said it was easy, I just said that if Apple applied 35% of the engineering effort they apply into creating vendor lock-in, part serialization and other twisted anti-consumer “solutions” they would be able to accomplish it.
No, it can’t be done. The iPhone is as thin as it is because the battery cover is glued to the battery. Take away the glue and it just can’t be that thin (or at least, if it was that thin it would be too weak - you’d probably snap the logic board by just putting it in a pocket - sometimes phones get pressed against your leg and legs are round).