Steemit has like over half a million users
I've made a small research few days ago. 421380 new accounts were registered in 2017. Only 113620 accounts (27%) made at least 5 posts/comments.
But I like the idea. Some users already tried to to convince Steemians write a letter to add STEEM and SBD on some big exchanges. But you make it a little bit simpler with your letter template)
Customer relations is a very important aspect for all businesses, especially those that NEED US!
At here is the point. Big exchanges do not like small volume traded altcoins. And also their support is very-very poor (we can see a lot of complaints here on Steemit - people have problems with verification, account blocks, etc. And support even do not reply on their tickets).