+significant and unknown set of new problems, including new bugs.
This reminds me of the time they lifted entire streets in Chicago by 14 feet to address new urban requirements. Chicago, we can safely assume, did not have the option of just starting a brand new city a few miles away.
The interesting question here is should a system design that works quite well upto a certain scale be abandoned in order to extend its market reach.
On the contrary, it's been discussed for ages. But it's a huge change, with only modest advantages.
I'm skeptical of the ROI to be honest. Not that is doesn't have value, but that it has more value than the effort.