Ritual tablets not drop if you farm mechanic directly.

They just dont drop.
GGG PLS add tablets in ritual market or up drop rate.

Strange. I don't have this issue. I mean their drop rate is low yes, but it's enough for sustain and I use them for every map so far.

I rarely drop ritual tablets as well. All other tablets, specially if using 1-2 tablets that contain a league mechanic, are plenty (e.g. Abyss, Delirium). But when doing Rituals with 2 Ritual tablets I rarely drop one(!) ritual tablet in all ten maps I do with the tablets. This needs to be adjusted, I already have all Precursor related atlas passive points.