Treble (which launched with Oreo) requires a different partition layout, a rather significant change to do on a running system. If anything, Oreo would see low

Treble (which launched with Oreo) requires a different partition layout, a rather significant change to do on a running system. If anything, Oreo would see lower uptake due to Treble, although that's mitigated by not making Treble a requirement for Oreo upgrades (ie. even if your device was upgraded to Oreo from something < 8.0, Treble still won't help you)