I think the assumption that lower root staking APY on $TAO will incentivize people to move to dTAO is flawed. Those with the risk profile to move have already done so. Taking away root APY will likely cause the majority of people to just sit on their $TAO. The APY is nice-to have, but the primary reason people hold $TAO is to speculate on its price, not to get staking APY.
Moreover, I think there's too much rush to reduce root APY, mostly by people who are down on their subnet investments. Eventually everything will sort itself, but there's too much impatience. I personally am looking forward to see which subnets will differentiate themselves from the vaporware and provide a strong enough value proposition to compete with $TAO price action wise. This will come gradually, not immediately.