The points given aren’t really that accirate. The main reason for prebuilts is for people to avoid building it themselves and to be able to bundle all the items under one company for warranties and such.
Prebuilts have the same issue with knowing the parts. If I see a company with two builds, but with the 5600/RX6600XT and 5600XT/RX6650XT they mentioned how do you know which one is better? You’re in literally the same predicament. That’s why companies now show FPS estimates for games as an extra perk but generally, buyers just look at the price and buy what’s in their budget, typically around the xx60 product range and an R5/i5 to go with it.