That is a great example of why this idea is completely infeasible. You can't replace a small component to get NFC. NFC requires a large antenna (think roughly t

That is a great example of why this idea is completely infeasible. You can't replace a small component to get NFC. NFC requires a large antenna (think roughly the size of a credit card). That has RF implications with other emitters ont he device (BT, Wifi, LTE). Also, all the RF modules in a PhoneBloks phone would require individual shielding to pass regulatory compliance (since the phone will never be tested as a whole the individual parts have to be certified), which will significantly increase their size and cost.