The problem is now you cannot choose because the factories/machines that make SLC are all gone.

You can still get pure SLC flash in smaller sizes, or use TLC/QLC in SLC mode.

I much rather have 64GB of SLC at 100K WpB than 4TB of MLC at less than 10K WpB.

It's more like 1TB of SLC vs. 3TB of TLC or 4TB of QLC. All three take the same die area, but the SLC will last a few orders of magnitude longer.

SLC are produced, but the issue is that there is no (I'm aware of) SLC products for consumer market