Not even close to 200 million votes for witnesses, and it is likely that it never will. Similarly, 75 million is 20% of the total supply of STEEM, not SP. And also similarly, it is very unlikely that anything close to 350 million total STEEM will ever power up as SP.

75 million is 37.5% of the currently powered up SP, not 20%. 37.5% is easily more than enough exercise total control given that not all of the powered up SP votes.

In theory, in some extreme hypothetical, 75 million might not be enough for total control, but in reality that is very unlikely.