So? RFID chips are easy to find with a directional antenna on the reader and a chisel. Or you can just take a microwave apart and use it to fry the RFID hidden inside the carbon fiber frame. Thing is, if you made a requirement that all bikes must have a serial number stamped on a list of locations and not defaced, if it's been puttied over, you know the owner's up to no good. Same way that VIN numbers are with a car.
Plus, your average Joe who is looking at craigslist bikes is going to be able to spot a VIN that's been tampered with but probably won't bother having an RFID reader.
You can guarantee that if it is possible to gather information about your habits, it will be misused.
Would you like your mailbox stuffed with flyers from every bike shop you cruise by? Do you want to be dragged into court because you happened to be biking by the scene of a crime, even if you weren't involved because the cops don't want to actually investigate? Do you want a rouge LBS to drum up business by subtly damaging new bikes made by the competing LBS now that they can pick them out of a big bikerack?
I sure as hell won't "enjoy" extra marketing media being sent to me.
It's going to cost a lot fewer pennies to stamp a serial number on two or three more places than just the bottom bracket than it does to add a few $0.40 RFID tags. But this is going to add up. Given that most of the big players make millions of bikes each year, the cost of RFID tags is going to have a material effect on profitability. Increase the cost by a buck and suddenly you are talking about millions of dollars.
And even though RFID readers are "cheap", it also adds up.
So, unless it's either a feature that people want to have or a legal requirement, nobody's going to be too interested in it.