Is there a term for a meaning that is wrong or different but about to be accepted by the majority? [closed]

Consider calling it a misnomer.

misnomer noun 1 A wrong or inaccurate name or designation. ‘morning sickness is a misnomer for many women, since the nausea can occur any time during the day’ - lexico

Wikipedia notes that:

A misnomer is a name that is incorrectly applied to a thing. Misnomers often arise because something was named long before its correct nature was known, or because an earlier form of something has been replaced by something to which the name no longer applies.

In your example, speedpaint is a misnomer because the video might not be about painting. The term time-lapse works more generally because it refers to the video production technique rather than the 'painting' technique.

Note that misnomers don't need to be a term misused by the majority (so perhaps doesn't exactly address your question). They just need to be inaccurate.