I have now read the white paper, page 20: https://steem.io/SteemWhitePaper.pdf

But it's not written there that the "house", i.e. the steemit company, gets 90%. What is written is, that out of a million of items (i.e. blog posts as far as I understand), the most popular 100 get 33,3% of the value, and the next 10.000 get another 33,3% and the rest of the 989.900 get the last 33,3% of value. So the 1% most popular posts get 66,6% of all value.

So it is indeed very hard to make serious money here. You need to belong to the top 1% of the most popular posters.

Additionally the owners of steemit and their friends seem to hold 87% of Steam Power or SD, so they can decide who is popular and who not. Of course this could make it really like a lottery...