Given that almost 90% of all blocks are solved by approximately only 10 pools, it may seem as though these 10 miners control 90% of the blocks.
Dont get me wrong, I believe OP's research has some flaws if it came to that conclusion, I just havent had time to read it.
My issue with this specific argument is how long would it take word to spread of a pool acting maliciously? How long would it then take word to spread far enough to significantly impact their hashrate? Lastly, how long would it take someone with 51% hashrate to do damage to Bitcoins reputation or worse?
If the former is > latter, effectively they do control the hashrate.
It only takes a short time of a few pools having "bad luck" to build up a longer chain.