The film emulsions are different from 30 years ago.
The subbing layers and other components are different from 30 years ago.
The sources for paper are different from 30 years ago.
The entities that can provide the narrowly specified, very high grade papers required are very, very, very different from 30 years ago.
The printers who print both colour and information on to backing paper are different from 30 years ago.
The inks used in that printing are different from 30 years ago.
The conditions under which film is distributed and retailed are different from 30 years ago.
And the problems with mottling, wrapper offset and other backing paper issues with 120 film all involve interactions between all the components.
I guess we also agree that all these components changed considerably and many times since 1901. Was is it only in the late 80s and early 90s that 120 film type has been faultless? I don't know but I guess no.