> has been tried a bunch of times in all sorts of different environments

Has it? When, where and with what technology?

> Predictability is really important and ridership drops as soon as users start having to plan too far ahead

Uber etc have proven this to be patently false. Existing buses are experiencing dropping ridership - Uber is not.

> won't be able to take advantage of things proven to make buses faster and more consistent

You're replacing buses with auto-shuttles. Just let the shuttles use the bus lanes.

> bus lanes, reducing stop count, transit priority signals

All of these are usable if you widen the scope to include auto-shuttles.

> consistency and response times gained by dynamic routing can easily be overshadowed by increased variability

What is the difference between Busing and Shuttles here? A bus user can keep yanking the stop cord, there can be 1 or 2 disabled passengers who take several minutes to board, there can be 50 children getting on / off. These issues are constants and all are improved with demand based shuttles.