I have estimated that 20% of the necessary stake is usually all that is required to elevate a witness to the top 20 in normal circumstances, because others will vote for them too. A third of extant stake can't simply overwhelm all opposition, but, as you point out, opposition won't be all there is.
Thanks!
In my latest post there is a link to an old post about reducing witness votes to 7, a change for just such an occasion.
It is still stake based, so even with sock accounts it doesn't matter. It would if it was one vote an account though
Each sock would have the 7 votes, bypassing the restriction by employing the socks to split the VP amongst them.
Yes, but splitting the stake doesn't generate more stake, it dilutes the vote of each. Even with a massive stake like Steemit's, this would dilute it sufficiently that several of the large whales would be able to counter in some way.