In a now closed thread @Anders_ASUS said, and I quote "We normally update every other month. If any major security risk has been discovered, then we will do our best to push the next security update as fast as possible"..... my Asus Zenfone 8 is still on 5th April security update and even with my basic maths that's 3 months tomorrow!!!!
Project treble was all about security updates to be non dependant on oem's bulls#it updates and lazy development. Asus may not have heard of it... Also not heard of overheating and battery drain, making the phone usable for leveling a table in a restaurant... Or not - too thick for that.
Btw you can't compare Pixel's release schedule to any other brand, it will always be somehow faster because it doesn't need to be "reworked" for the custom roms. And ZenUI has lot of customizations, they just work under the hood and are less "sparkly" than others.