Irony/sarcasm punctuation

I wonder why there's still no standard way to denote sarcasm/irony in written English other than doing it well (or obvious) enough that people recognize it.

Some historical punctuation proposals:

• 1668: John Wilkins, in his famous An Essay towards a Real Character and a Philosophical Language, proposed using an inverted exclamation mark () to punctuate ironic statements.
  
• 1841: Marcellin Jobard, a Belgian newspaper publisher, introduced an irony mark in the shape of an oversized arrow head with small stem (rather like an ideogram of a Christmas Tree) and used in various orientations (on its side, upside down, etc.) to mark ?a point of irritation, an indignation point, a point of hesitation.
  
• 1899: The irony point () was proposed by the French poet Alcanter de Brahm (alias Marcel Bernhardt) in his 1899 book L'ostensoir des ironies to indicate that a sentence should be understood at a second level (irony, sarcasm, etc.)
  
• 1966: Herv Bazin, in his 1966 essay Plumons l'Oiseau (?Let's pluck the bird), used the Greek letter with a dot below for the same purpose () in the same work, he proposed five other innovative punctuation marks: the ?doubt point (), ?conviction point (), ?acclamation point (), ?authority point (), and ?love point ()
  
• 1900s: Tom Driberg recommended that ironic statements should be printed in italics that lean the other way to conventional italics.
  
• 2007: the Dutch foundation CPNB (Collectieve Propaganda van het Nederlandse Boek) presented another design of an irony mark, the ironieteken: ()
  

I kinda like Tom Driberg's idea of italics that lean the other way. Either way,I think we're due for some new punctuation.

Until then there's always</sarcasm>