We can discuss the numbers, but the point is that retention is horrible because stake weighting captures the rewards that are necessary to encourage content creation and drive Steem price up. HF21 dramatically increases the impact of stake weighting, and as a result the problems Steem social media suffers due to stake weighting are going to be dramatically increased as well.
Moving rewards from creation to curation does not demonetize bid bots at all. All bot operators need to do is pass some of their curation rewards on to compensate. Once that is done bid bots are more powerful than ever, due to the new rewards curve. It is the basic failure to encourage capital gains versus profiteering that actually creates dismal retention, not at what point profiteering extracts the rewards, that matters.
@paulag estimates her vote is ~25% of what it was before HF21, and Imma accept her estimate since I can't be bothered to calculate it. That means she can deliver but a quarter of the financial incentive to create content and engage with it she could when user retention was dismal and collapsing the market for Steem. Regardless of whether she retains 15% or 35% of her encouragement ability, the fact that it is dramatically reduced means that user retention is dramatically discouraged - from the point at which it was already existentially bad.
Consolidation of Steem is the problem, not the solution. The fewer users there are with Steem, the lower the price of Steem will fall. Consider what the price of Steem will be when the ultimate consolidation has occurred: one account has all the Steem. The price will be 0, because there will be no market for it.
Pogo famously said 'We have met the enemy, and it is us.' Profiteers are the enemy of Steem, and sadly have essentially all of it.