A very valid point you make. Currently the limited advertising interface steemit has, i.e. Promoted section, gets little to no traction and is actually seems to be a waste of resources. Advertising itself may not be the best solution.
I think what could potentially work is a goal orientated system that works like an automated tutorial system. Instead of encouraging newbs to post, it guides them to network, comment and connevt with people and gain followers, as soon as they unlock certain goals and followerships, post become available. They get rewarded for completing goals with posts and auto upvote from a whale account. Whales yo be paired with lower level accounts and to give at least 50 cent auto upvotes to sponsored accounts. Which is not much for them, but alot for lower level accounts. The higher rep the account gets to the greater the reward. Which will encourage users to constantly unlock new levels and goals. Kinda like a game.
RE: The FUNDAMENTAL issue of Steem nobody talks about... Part 1: Defining the problem (+ Bounty!)