Annoying chat spam limits social interaction

Social interaction is one of the most important aspects of WoW, and chat is the most important means of communication. Unfortunately, the possibility to chat is repeatedly destroyed by spammers who post the same advertisement every few seconds. The player posts the same line every five seconds (!) in the trade chat. For hours, for days: "WTB Cardinal Ruby 225 Gold each COD ME ALL YOU HAVE"

That means that only this single player posts the message 720x per hour (!) in the chat.

I know I can set it to Ignore; but is there no way, no interest in solving the problem in principle, by setting a limit, e.g. posting the same line only every 3 minutes?

And screw over raid making? Force them into permutations like
WTB Cardinal Ruby 225 Gold each COD ME ALL YOU HAVE
COD Cardinal Ruby 225g/each
Buying epic red gems via Cash on Delivery 225 each

Global is a ****show, use other less-crowded channels like General or Defense