they just removed the 50% discount today

i can imagine they're a bit tight to keep those prices viable while they also have enough compute to train their new models

I don’t think it is about viability. The Christmas discount was supposed to expire jan 15, then it was further expanded to jan 31.

The deal was too good to miss out on.

although apparently only the max subscription includes glm-5

No, GLM-5 is being rolled out to Max and Pro users first. They will later roll out to Lite users when capacity allows.

Yes, thank you for pointing that out. It's probably load management thing.