What country are you referring to? I know that in the UK it's often mixed, but in (Midwestern) America almost no one I've known has mixed tobacco with their cannabis.
https://www.inverse.com/article/32064-america-europe-tobacco...
But spliff smokers are in the minority in the US. Was more prevalent in the past when more people smoked tobacco.
Nowadays most people use carts / pens for cannabis use anyway.
I wonder if that's true or selection bias. Certainly we see more people with carts / pens, but I wonder if that's actually true of overall usage. Pens allow it to be less conspicuous and smelly which leads to more conspicuous usage, but flower smokers are still toking in basements and garages.