Why are memory modules so expensive?

Question

RAM

Hello.
Bought in March of this year 2 memory modules in citilink
Memory module CRUCIAL CT16G4SFD8213 DDR4 - 16GB 2133, SO-DIMM, Ret 2 pcs. 5500 rub.
total 11000 rub.
Now I'm checking the same modules
https:
//www.citilink.ru/catalog/computers_and_note... 9990 rubles and almost 20,000 for 2 modules.
Why has memory become so expensive (+9000)?

Answer 1

https://technopoint.ru/product/228337f8e6a23330/op...
In my city 8690 costs