during the Renaissance, the average person didnt know about Renaissance artists either.
The Renaissance is only monumental in historical context. during the Renaissance they knew it was some new shit, just like Henry and Martha knew it was some new shit when Part and Slave were doing whole cars on the 2s and 5s.
i think the purpose of Writing (not graffiti) has no real value outside of the Writing culture. For that reason, i doubt it will have much of an impact on humanity - even in 5000 years. However, what writing has done is bring together people of all races and socio-economic backgrounds unlike anything else in recent history except maybe sports. to that end, in the future i could see it recognized for that more than the actuall art.
as for old school writers and their egos, MAD MAD MAD MAD people get paid off of graffiti, including the creators of this site. the people who created, popularized and made it so cool that YOU wanted to be involved deserve all the passes they can get.