1) long range replay attack are what is a real issue, and is solved by bi-dir fobs. Only thing keeping them out of the market as a default is price. Issue descr

1) long range replay attack are what is a real issue, and is solved by bi-dir fobs. Only thing keeping them out of the market as a default is price. Issue described in the article is far less of a concern than what you mentioned, I put it in the category of Intel's Spectra - where if you already have such physical access to the device/CPU, there are easier ways... 2) Price - just the MCU is more than 10+ USD. Those MCUs are basically ASICs with a lot of stuff integrated (plus - automotive rating). Precise and stable OCX doesn't come cheap either... 3)There is no single chip solution in the automotive market that would integrate all functions (LF Rx, RF Tx+RX, transponder Rx+Tx). Additionally, RF bi-dir + passive LF is power hungry, and getting a year out of your standard CR2032 forget about it - so a more expensive power source needs to be used... 4)NFC is basically just only one of the aforementioned functions - similar to transponder Rx+Tx. 5) Oh it needs writable nonvolatile memory for a lot of reasons... - configuration to cover different vehicle/market/protocol variants, DTC, Secret Keys for pairing, unless you want your fob replacement price to skyrocket... Regarding fob price - keep in mind it's not just the electronics, although automotive MCUs have harder requirements to satisfy (op. range of temperature, voltage, very low quiescent current, very low ppm failures). Mechanics are expensive, although deceiving when you look at them. Keep in mind they go through some pretty nasty tests - including (and I kid you not) a washing machine test - basically testing if it will survive a washing machine.