If there are 2 memory slots and slots for SSDs (at least 2 x M.2 2280, and it is necessary to support Double-Sided SSD, otherwise the choice is reduced by 10 times on market) and the level of markup on memory/ssd from manufacturers, which literally reaches 4 times or more, it is more profitable for the buyer to take laptops with a minimum amount of RAM and SSD, if this sharply reduces the purchase price and when it is much more profitable to buy these components yourself at many times cheaper with a 5-10 year warranty (as opposed to 1-3 years as part of a laptop) and install for 5 minutes on your own.

Soldered memory makes sense only in one case - the maximum frequencies of the chips are at least lpddr5 7500+. In all other cases, the laptop must have 2 slots or the soldered memory must be at least 32GB, and preferably 64GB for models more expensive than $1300.