What's the current state of SMR technology? I noticed that all the high capacity drives (ie. 16+TB) are all CMR, and SMR drives top out at around 8TB. Is there a reason for this? Did WD and seagate stop developing SMR drives after the consumer backlash?

Imagine how long it would take to write 16Tb to an SMR drive... That's probably why there's no really large ones.

For sequential write workloads it shouldn't be much slower than CMR drives. They only get bad performance when overwriting existing data, especially if they're randomly spread out.