I don’t think the manufacturing cost is the driver there, the forced upgrade is. The argument isn’t for saving $1-2 per unit or whatever, but forcing customers to pay $100-200 more for that memory upgrade they’re not sure they need, but get because they can’t upgrade later.

thin and light

Yup, and that’s a big reason why I don’t buy those. Saving a little space and size is nice, but not at the cost of upgradability. In fact, that’s why I bought an E-series instead of the more expensive T-series, the E-series didn’t have soldered RAM.