There is no assumption. Just education and communication. Everyone can still chose what they prefer, but the majority will head towards what's better for all.
Time will tell. Editors start embracing syntax coloring. Github also start adding to it's viewer. Sure one can turn it off, and ignore it. Prefer the power of the eye detection than the help of tools.
Horses are preferred over a car in the past... but one day, machine will do a better job in all these. Still then, some people still prefer horses. That's alright.