English usage - food for thought

After an article called Which Language Rules to Flout. Or Flaunt? by two apparently well-known English grammarians, one prescriptivist and one descriptivist, on the subject of proper usage of English, JerryVNYC leaves this thought-provoking comment:

My current pet peeve is the common use of the contraction "it's" in place of the possessive "its", as in "The cat has it's own bed". I suggest that this misuse is due to the fact that we commonly create possessives by adding an apostrophe plus an "s" to nouns.

Stirring stuff.