"Hey someone committing a crime is writing notes to each other! Quick, order all pen manufacturers to send us copies of everything people are writing!"
Pencil manufacturers can't comply, either, because their pencils are not equipped with sensors and antennas. None of the mass-market writing instruments do.
To extend the analogy, the government might order all manufacturers to build sensors and antennas into every writing instrument. That might work, until people start smuggling cheaper, foreign-made, non-spying pens into the country.
"Sir the pen manufactures said they can't comply"
"Ok that's it, stop the sales of all pens"
Then everyone starts using pencils.