I think it's pretty common, you're just not reaching for the right set of "-ence" words.

Residence -> residential, Evidence -> evidential...

Jurisprudential, existential, penitential...

The only thing is that about half have become "having characteristics related to the thing" instead of "about the thing". Words like consequential, pestilential, preferential have a common usage in this realm but still can be used in the "discussion about a thing" sense.

Since you're curious: in the original Latin you'd be looking for words of 3rd declination that have "ent" and, depending on case, end with -ens (contraction of ent+s), -entis, -entia or something like that.

I guess English took (ens -> ence) and (entia + l -> ential).

Reference -> Referential Difference -> Differential Prudence -> Prudential (now I understand the origin of this name)