They already did; these have both been built-in for years. The flashlight was added in Android 5.0 (https://www.androidauthority.com/android-5-0-lollipop-offici... I'm having a harder time figuring out when the barcode scanner was added, but my phone does it automatically in the camera app now.
(Disclosure: I work for Google, speaking only for myself)
If Android has a built-in QR scanner now, that must be something that came with Android 11, but September 8 2020 cannot qualify as "for years". It takes a while for OEM's to catch up as well.
There are certainly Android phones that ships with this feature (QR-scanner), but stock Android 10 does not. (Google lens != Standard Photo app).
If you know about it, you can start "Google lens" app, but that app does not even come up as a suggestion when you type QR scanner into the play store. I.e. even when you have a QR scanner available on your phone, you wouldn't know unless you somehow knew about "Google lens".
[1] https://medium.com/turunen/built-in-qr-reader-on-android-696...